JP2002318366A - Observation optical system, imaging optical system, and apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an observation optical system which makes the observation of a bright display image possible, facilitates assembly, is strong to impact, such as vibration, is light, is compact and is well corrected of aberrations. SOLUTION: The eyepiece optical member for guiding the observation image formed by an observation image forming material 5 to an exit pupil 1 is constituted by cementing and arranging a first prism 3 having a first incident surface 33 , a reflecting surface 32 and a first exit surface 31 with a first prism medium held in-between and a second prism 4 having a second incident surface 42 and a second exit surface 41 with a second prism medium held in-between by putting a hologram element 6 between the first exit surface 31 and the second incident surface 42 . The reflecting surface 32 has positive power. The first exit surface 31 and the second incident surface 42 are formed of planes or cylindrical surfaces and the hologram element 6 also consists of the plane or the cylindrical surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an observation optical system, an imaging optical system, and an apparatus using the same, and more particularly to an observation optical system and an imaging optical system which can be held on the head or face of an observer. The present invention relates to an optical system that can be added to an image display device or the like.

[0002]

2. Description of the Related Art In recent years, an image display device, particularly an image display device of a type worn on the head or face, has been actively developed for the purpose of allowing individuals to enjoy a large-screen image. In recent years, the spread of mobile phones and the need to view images and character data of mobile information terminals on a large screen have been increasing.

Under such circumstances, an optical system using a half mirror as a diagonal mirror for branching an optical path into a prism optical system including a concave mirror having a small eccentric amount is disclosed in Japanese Patent Laid-Open No. 7-14 / 1995.
0414 and JP-A-9-171151.

Also, US Pat. No. 5,093,567,
JP-A-2000-241751, JP-A-2000-1807
No. 87 proposes an optical system in which a triangular prism and a first prism having a convex lens function are arranged on the eye side, and a second prism is arranged with a small air gap. An observation optical system that bends an optical path without loss of light amount by utilizing a total reflection phenomenon generated by a difference in refractive index between glass and air due to an air gap between minute prisms has been proposed.

As an observation optical system using a hologram element, US Pat. No. 4,874,214 has been proposed. In this observation optical system, hologram elements are used at two positions on a plane inclined mirror surface and a spherical substrate shape.

[0006]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 7-14 / 1994.
No. 0414 and Japanese Patent Application Laid-Open No. 9-171115, the oblique mirror disposed in the prism optical system is constituted by a half mirror. For this reason, the light emitted from the image display element passes through the half mirror twice, so that the light amount is reduced to １ ／ and the displayed image is darkened. In order to prevent this, it is necessary to illuminate the image display element with brighter illumination or the like that consumes more power. If the light source cannot be brightened due to the power consumption or the capability of the light source element, it is impossible to observe the display image under the bright sun.

Also, US Pat. No. 5,093,567,
JP-A-2000-241751, JP-A-2000-1807
Since the observation optical system 87 has a minute air gap between the two prisms, it is necessary to adjust the optical axes of the prisms. Therefore, the assembly cost increases. Further, there is a problem that the optical axis is likely to be shifted when a shock or vibration is applied to a device including these observation optical systems.

Further, the optical system proposed in US Pat. No. 5,093,567 is large in size and heavy in weight because it is a relay optical system, and can be used in addition to a portable telephone or a portable information terminal. It will be difficult.

The observation optical system proposed in US Pat. No. 4,874,214 has a hologram element having a spherical shape. By the way, there are two types of hologram elements: an optical power based on a geometric shape and an optical power based on a diffraction effect of the hologram element. For example, two types of power in the case where a hologram element is provided on a spherical substrate member will be described with reference to the drawings. As shown in FIG. 29A, the hologram element has a pitch of a periodic structure inside the hologram element. , And has optical power due to the geometrical shape thereof, as shown in FIG. 29B. When the radius of curvature of the hologram substrate is R, the optical power Φ can be calculated by the following equation in the case of a conventional optical refraction lens and a reflecting mirror.

In the case of a refraction system: Φ = (n-1) (1 / R) In the case of a front mirror: Φ = 2 / R In the case of a back mirror: Φ = 2n / R, where Φ: optical power n due to geometrical shape : The refractive index of the medium R: the radius of curvature of the hologram substrate Therefore, when comparing the front mirror and the rear mirror, in order to obtain a certain amount of optical power depending on the geometrical shape, the rear mirror is only 1 / n with respect to the front mirror. It can be seen that it can be configured with a gentle radius of curvature R.

That is, by filling the inside of a reflection type hologram element with a medium having a refractive index of n such as glass or plastic like a back mirror, even if the geometrical shape has a gentle radius of curvature R, the optical power due to the large geometrical shape can be reduced. Means to be obtained.

As described above, by adopting a configuration in which a large optical power can be generated with a gentle radius of curvature R in the optical system, the aberration generated on the hologram surface can be suppressed.

However, US Pat.
In the observation optical system described in No. 4, since the space between the plane and the spherical surface is not filled with the glass or plastic medium, the geometrical shape is reduced to secure a necessary amount of optical power by the spherical shape. It is necessary to use a curvature radius R.

If a geometrical shape is formed with a smaller radius of curvature R, aberrations occurring on the reflecting surface will increase, making it difficult to display a good image. Further, since there is no optical surface in the optical path between the image plane and the plane, it becomes difficult to satisfactorily correct the distortion.

The hologram surface in US Pat. No. 4,874,214 is spherical. Generally, as a method of attaching a hologram, there are a method of attaching a film-like hologram to a substrate surface, and a method of spraying a liquid photopolymer or the like serving as a hologram recording material onto the substrate surface. In the latter case, Exposure and development processing must be performed after spraying, and in consideration of mass productivity, a method in which a film-shaped hologram element capable of exposure and development processing is bonded to a substrate before bonding is preferable.

However, generally, a hologram in the form of a film is supplied in a flat form from a manufacturer.
It is not easy to uniformly attach a planar film-type hologram element to a three-dimensional curved surface.

The present invention has been made to solve such problems of the prior art, and its object is to enable observation of a bright display image, to be easy to assemble, and to be resistant to shocks such as vibration. It is an object of the present invention to provide an observation optical system for an image display device, which is light, compact, and capable of observing a display image in which aberrations are well corrected, an imaging optical system, and an apparatus using the same.

[0018]

According to the present invention, there is provided an observation optical system comprising: an observation image forming member for forming an observation image to be observed by an observer; and an observation image formed by the observation image formation member. In an observation optical system having an eyepiece optical member that guides to an exit pupil formed at an observer's eyeball position, the eyepiece optical member includes at least a first prism member and a second prism member, and the first prism includes: at least,
A first incident surface for interposing a first prism medium between the first prism medium and a light incident from the observation image into the first prism; a reflecting surface for reflecting the light inside the first prism;
A first emission surface for emitting a light beam outside the prism, wherein the second prism receives at least a light beam emitted from the first prism into the second prism with a second prism medium interposed therebetween. And a second exit surface for emitting light rays out of the second prism. The first prism and the second prism are connected to the first exit surface and the second incident surface. And the reflection surface of the first prism is formed into a concave curved surface that gives a positive power to a light ray when reflected, and the first emission The surface and the second incident surface may be formed from a flat surface or a cylindrical surface, or may be formed from a spherical surface or a toric surface satisfying the following conditions.

-2.0 <Da / Ra <2.0 (2) -0.05 <Db / Rb <0.05 (3) where Ra and Da are larger in curvature. Rb and Db are the radius of curvature and the outer diameter of the axis having the smaller curvature, respectively.

According to another aspect of the present invention, there is provided an image pickup optical system for picking up an object image, which is arranged on an image plane, and for reducing the brightness of a light beam from an object, arranged on a pupil plane. In an imaging optical system having a brightness stop and an imaging optical member arranged between the image plane and the pupil plane, for guiding the object image to the image plane, the imaging optical member is at least a A second prism member and a first prism member, wherein the second prism causes a light beam from an object that has passed through the aperture stop to enter the second prism at least with a second prism medium interposed therebetween. A third incident surface, and a third exit surface for emitting a light beam outside the second prism;
The first prism has at least a fourth incident surface on which the light emitted from the second prism enters the first prism with the first prism medium interposed therebetween, and reflects the light inside the first prism. And a fourth exit surface for emitting a light beam outside the first prism.
The prism and the first prism are configured so as to be joined and disposed with the hologram element interposed between the third exit surface and the fourth incident surface, and the reflection surface of the first prism is configured to reflect light when reflected. The third exit surface and the fourth entrance surface are formed of a flat surface or a cylindrical surface, or a spherical surface or a toric that satisfies the next condition. It is characterized by being formed from a surface.

-2.0 <Da / Ra <2.0 (2) -0.05 <Db / Rb <0.05 (3) where Ra and Da are larger in curvature. Rb and Db are the radius of curvature and the outer diameter of the axis having the smaller curvature, respectively.

Hereinafter, the reason and operation of the above configuration in the present invention will be described.

First, the observation optical system will be described.

An observation optical system according to the present invention comprises an observation image forming member for forming an observation image to be observed by an observer, and an observation image formed by the observation image formation member on an exit pupil formed at an observer's eyeball position. In an observation optical system having an eyepiece optical member for guiding, the eyepiece optical member includes at least a first prism member and a second prism member, and the first prism has at least a first prism medium interposed therebetween. ,
A first incident surface that causes light rays from the observation image to enter the first prism, a reflecting surface that reflects light rays within the first prism, and a first emission surface that emits light rays outside the first prism. And the second prism has at least:
There is a second incident surface through which a light beam emitted from the first prism enters the second prism with a second prism medium interposed therebetween, and a second exit surface through which the light beam exits outside the second prism. are doing.

As described above, by filling the inside of the eyepiece optical member with glass or plastic material, the optical power due to the surface shape of each optical working surface is increased, and aberrations such as spherical aberration and coma aberration are favorably corrected. are doing.

Further, in the observation optical system according to the present invention, in addition to the above configuration, the first prism and the second prism sandwich a hologram element between the first exit surface and the second entrance surface. It is configured so as to be joined and arranged.

If a hologram element is used as a diagonal mirror for branching the optical path, a diffraction efficiency close to 100% can be obtained at the time of reflection diffraction, and a bright image display without loss of light quantity can be realized. Further, if two prisms, a prism on the image display element (observation image forming member) side and a prism on the eye side, are joined to each other with a hologram element interposed therebetween to constitute one member,
It is possible to eliminate the misalignment of the optical axis and the complicated setting during the assembly due to the presence of the air gap, and to achieve an observation optical system that is easy to assemble and resistant to shocks such as vibration.

Further, if the hologram element is sandwiched between the first prism and the second prism and joined, the hologram element can be protected from dust. Therefore, it is possible to prevent dust and the like from being magnified and observed without providing a separate dust protection member. In addition, it is possible to prevent the hologram element from expanding due to the invasion of moisture from the outside into the hologram element and changing the peak wavelength of diffraction efficiency.

Further, in the observation optical system according to the present invention, in addition to the above-mentioned configuration, the reflecting surface of the first prism is formed into a concave curved surface which gives a positive power to the light beam when reflected.

Further, the observation optical system of the present invention does not form an intermediate image between the image display device and the eye. That is, since it has no relay optical system, it is configured as a light and compact observation optical system.

Further, in the observation optical system of the present invention, the first entrance surface of the first prism is formed into a curved surface shape that gives power to light rays when transmitted, and the second exit surface of the second prism is
It is desirable to form the light beam into a curved surface that gives power to the light beam when transmitted.

In the observation optical system of the present invention, it is preferable that the first prism medium and the second prism medium are composed of the same kind of medium.

Further, in the observation optical system of the present invention, it is preferable that the surface shape of the first exit surface of the first prism and the surface shape of the second incident surface of the second prism are substantially the same.

Here, the term “substantially the same shape” means that a difference in surface shape within a range of a manufacturing error is allowed.

In the observation optical system of the present invention, ghost light does not enter the observer's eyeball on non-optically active surfaces other than the optically active surfaces of the first prism and the second prism that transmit and reflect light rays. It is preferable to provide such a ghost light removing member.

It is effective to provide the ghost light removing member on the bottom and side surfaces of the eyepiece optical member when the first incident surface of the first prism is defined as the upper surface. Further, areas outside the effective beam diameter in the first incident surface, outside the effective beam diameter in the reflecting surface of the first prism, and outside the effective beam diameter in the second exit surface of the second prism are also non-optically active surfaces. It is also effective to provide a ghost light removing member in this part.

In the observation optical system according to the present invention, it is preferable that the first incident surface of the first prism has a rotationally asymmetric curved surface.

As described above, by disposing the transmission surface (the first incidence surface of the first prism) on the front surface of the image forming member such as the image display device, the distortion can be corrected well. The shape of the front surface of the image forming member can be formed by a rotationally symmetric surface.However, in order to reduce the eccentric aberration when the optical working surface is eccentrically arranged for the purpose of miniaturizing the observation optical system, It is more desirable to use a free-form surface.

In the observation optical system according to the present invention, the rotationally asymmetric curved surface of the first entrance surface of the first prism has a symmetrical surface of one.
It is composed of a free-form surface consisting only of surfaces, and its only symmetry surface is
It preferably coincides with the folded surface (YZ plane) of the optical axis.

It is preferable that the observation optical system of the present invention is configured such that the hologram element corrects the chromatic aberration of magnification of both the rotationally symmetric component and the rotationally asymmetric component by reflecting and diffracting the light beam.

High contrast can be realized by correcting the chromatic aberration of magnification of the rotationally symmetric component and the rotationally asymmetric component with the reflection type hologram element.

In the observation optical system of the present invention, the hologram element joined and disposed between the first prism and the second prism comprises a reflection type hologram. By making the angle deviated from 45 ° with respect to the axial principal ray from the surface of the observation optical system closest to the exit pupil to the exit pupil), the total thickness of the observation optical system is reduced,
Compactness and light weight can be realized. In order to correct the eccentric aberration caused by shifting the oblique mirror composed of the hologram element from 45 °, the surface from which the light from the image display device is incident on the prism, the surface which reflects the diffracted light from the reflective hologram element, the eye A free-form surface is arranged on each of the surfaces in front of the hologram element, and the substrate shape of the reflective hologram element surface is given a power, so that the coma aberration and the field curvature are favorably corrected.

[0043] That is, as shown in FIG. 24, from the surface 4 ₁ of the axial principal ray 2 and most exit pupil side of the tangent plane and the observation optical system at the position A and the substrate surface intersects the holographic optical element 6 to the exit pupil 1 It is important that the following formula is satisfied, where θ is the angle formed by the on-axis principal ray 2.

45 ° <θ <85 ° (1) When the angle θ is smaller than the lower limit of 45 ° of the condition (1), the inclination of the oblique mirror composed of the hologram element becomes too small, and the observation optics becomes too small. The system becomes thick, resulting in a large and heavy observation optical system. When the angle θ is larger than the upper limit of 85 °, the eccentricity of the observation optical system is too large,
It becomes difficult to correct the eccentric aberration, and it becomes difficult to observe an image in which the contrast is high and the distortion is well corrected.

More desirably, it is important to satisfy the following expression.

55 ° <θ <80 ° (1-1) The meanings of the lower limit and the upper limit of this conditional expression are the same as described above.

More desirably, it is important to satisfy the following expression.

65 ° <θ <75 ° (1-2) The meanings of the lower limit and the upper limit of this conditional expression are the same as described above.

In the observation optical system of the present invention, the first prism member and the second prism member fill the interior of the observation optical system with glass, plastic material, or the like, so that the optical shape of each optical working surface can be improved. The power is increased, and aberrations such as coma and field curvature are satisfactorily corrected.

Incidentally, in the present invention, the reflection type hologram element arranged on the oblique mirror is generally a film type flat hologram element, and the first hologram element is a substrate to which this flat hologram element is attached. The first exit surface of one prism and the second entrance surface of the second prism are desirably a flat surface and a cylindrical surface.

Further, even if the substrate to which such a plane hologram element is adhered is a spherical or toric surface, if the following conditional expression is satisfied, mass production is performed using such a plane hologram element. It is possible.

-2.0 <Da / Ra <2.0 (2) -0.05 <Db / Rb <0.05 (3) where Ra and Da are larger in curvature. Rb and Db are the radius of curvature and the outer diameter of the axis having the smaller curvature, respectively.

In the above conditional expressions (2) and (3), the lower limits of -2.0 and -0.05 are the limits in the case of attaching the hologram element to the concave surface, and the upper limits of 2.0 and -0.05, respectively. , 0.05 are the restrictions when pasting to the convex surface. If the upper and lower limits of the above conditional expression are exceeded, the flat hologram element becomes wrinkled at the periphery of the curved surface, so that uniform bonding becomes difficult and the optical performance of the hologram element cannot be obtained.

More preferably, it is important to satisfy the following expression.

−2.0 <Da / Ra <2.0 (2-1) −0.02 <Db / Rb <0.02 (3-1) The lower limit of these conditional expressions and The meaning of the upper limit is the same as described above.

More preferably, it is important to satisfy the following expression.

-2.0 <Da / Ra <2.0 (2-2) -0.015 <Db / Rb <0.015 (3-2) The lower limit of these conditional expressions and The meaning of the upper limit is the same as described above.

Further, in the observation optical system according to the present invention, the surface shape of the second exit surface of the second prism is such that at least one of rotationally asymmetric coma and astigmatism generated by the eyepiece optical member is eliminated. It is preferable that it is constituted by a rotationally asymmetric curved surface shape having a function of correcting.

In the observation optical system of the present invention, the rotationally asymmetric curved surface of the second exit surface of the second prism has a symmetric surface of 1
It is composed of free-form surfaces only, and the only symmetric surface is
It preferably coincides with the folded surface (YZ plane) of the optical axis.

In the present invention, the surface constituting the first prism and the surface constituting the second prism are rotationally asymmetric such as a free-form surface in order to provide rotationally asymmetric distortion correction and an optical system having good telecentricity. Although a surface is desirable, it is also possible to form a rotationally symmetric surface such as a spherical surface, an aspherical surface, or an anamorphic surface.

In the observation optical system of the present invention, the light beam from the observation image formed by the observation image forming member is transmitted through the first incident surface to enter the first prism, and the incident light beam is converted into a volume hologram. On the other hand, the light is incident at a first incident angle within the range of the angle selectivity, is reflected and diffracted, and then is reflected by the reflecting surface. The reflected light beam re-enters the volume hologram surface at the second angle of incidence, but falls outside the range of the angle selectivity of the volume hologram, so that the diffraction efficiency becomes extremely low, and the first exit is substantially performed as it is. The light passes through the surface, passes through the second incident surface, and is emitted into the second prism.

The light beam entering the second prism passes through the second exit surface as it is, exits from the second prism, and
It will be guided to the observer's eyeball.

The observation optical system according to the present invention comprises an optical member such as a prism, a parallel plate glass, or a positive or negative lens between the first entrance surface of the first prism and the observation image forming member. May be arranged.

In addition, the observation optical system of the present invention includes, for example, a prism, between the second exit surface of the second prism and the exit pupil.
An optical member such as a parallel plate glass or a positive or negative lens may be arranged.

By the way, for example, an LCD is used for an image display element.
In the case of an image display device such as a (liquid crystal display device), it is necessary to perform enlarged display with an optical system having good telecentricity in order to display a high-contrast image. In addition, as described later, these configurations of the optical system of the present invention can be applied not only to the observation optical system but also to the imaging optical system. It is important to capture an image with an optical system having good telecentricity in order to prevent shading or the like.

In the present invention, since the eye relief is long with respect to the focal length of the entire optical system, the principal ray of the off-axis light beam is inclined toward the image display element in the direction of convergence.
In order to increase the telecentricity of the optical system, to realize a compact optical system with a long eye relief, place a negative power near the image display device (imaging device) in the optical path, and place it on the eye side (object side). It is desirable to place a positive power in ().

This is a configuration in which the retrofocus type optical system is inverted. That is, it is important to have negative power on the oblique mirror surface near the image display element in the optical system,
In particular, in order to ensure telecentricity over the entire screen having different aspects, it is important that the negative power of the oblique mirror corresponding to the axis having the larger aspect ratio of the oblique mirror is large.

When there is no eccentricity in the X-axis direction (all embodiments described later), the length of the image display element in the X-axis direction is D
When the length in the x and Y axis directions is Dy, that is, when the aspect ratio is Dx: Dy, and when the radius of curvature of the oblique mirror surface in the X axis direction is Rx and the radius of curvature in the Y axis direction is Ry If the following conditional expressions are satisfied, telecentricity can be ensured and optical performance is good.

−1.0 ≦ Dx / Rx ≦ 0 (4) −1.0 ≦ Dx / Ry ≦ 0 (5) If the upper limit of 0 in these conditional expressions is exceeded, the oblique mirror surface Has a positive power, it tilts in the direction in which the chief ray tilt angle further converges, and it becomes impossible to capture a high-contrast image from the image display element. When the lower limit of -1.0 is exceeded, the image display element is too large or Since the negative power of the oblique mirror surface is too large, the inclination of the principal ray tends to be divergent, and an image with high contrast cannot be taken from the image display device.

More desirably, it is important to satisfy the following expression.

−0.5 ≦ Dx / Rx ≦ 0 (4-1) −0.5 ≦ Dx / Ry ≦ 0 (5-1) The meanings of the lower and upper limits of these conditional expressions are as follows. Same as above.

More preferably, it is important to satisfy the following expression.

−0.1 ≦ Dx / Rx ≦ 0 (4-2) −0.1 ≦ Dx / Ry ≦ 0 (5-2) The meanings of the lower and upper limits of these conditional expressions are as follows. Same as above.

With the above configuration, the hologram element is used on the oblique mirror surface having the substrate shape of the flat surface and the cylindrical surface, or the condition that the hologram element does not wrinkle in the peripheral portion when the flat hologram element is attached. (2),
(3) By using a hologram element on an oblique mirror surface having a spherical or toric substrate shape that satisfies (3), it is not necessary to provide a half mirror for branching the optical path or provide an air gap. It is possible to observe images, and it is easy to assemble, resistant to vibration and other shocks, light and compact, and easy to attach holograms, and it is possible to observe well-corrected display images. Observation optical system and apparatus using the same can be obtained.

Incidentally, these configurations of the optical system of the present invention are as follows.
Application to not only an observation system but also an imaging system is possible.

An image pickup optical system according to the present invention includes an image pickup device for picking up an object image, which is disposed on an image plane, and an image pickup element, which is disposed on a pupil plane.
In an imaging optical system having a brightness stop for reducing the brightness of a light beam from an object, and an imaging optical member arranged between the image plane and the pupil plane, for guiding the object image to the image plane, The imaging optical member includes at least a second prism member and a first prism member.
A prism member, wherein the second prism has at least a third incident surface that interposes a second prism medium and allows light rays from an object that has passed through the aperture stop to enter the second prism. A third exit surface for emitting a light beam out of the second prism, wherein the first prism transmits the light beam emitted from the second prism at least with the first prism medium interposed therebetween; A fourth incident surface for entering light into the inside, a reflecting surface for reflecting light inside the first prism, and a fourth surface for emitting light outside the first prism.
And an emission surface. Further, the second prism and the first prism are configured so as to be joined to each other with a hologram element interposed between the third exit surface and the fourth incident surface. Further, the reflecting surface of the first prism is formed into a concave curved surface that gives a positive power to a light ray when reflected.

Then, the third exit surface and the fourth entrance surface are formed from a flat surface or a cylindrical surface.

Alternatively, it is formed from a spherical or toric surface satisfying the following conditions.

-2.0 <Da / Ra <2.0 (2) -0.05 <Db / Rb <0.05 (3) where Ra and Da are the ones having larger curvatures. Rb and Db are the radius of curvature and the outer diameter of the axis having the smaller curvature, respectively.

That is, in the observation optical system of the present invention,
In the imaging optical system of the present invention, the observation image forming member, the exit pupil, and the eyepiece optical member are replaced with an imaging element, a brightness stop, and an imaging optical system, respectively.

It is preferable that the imaging optical system be configured in accordance with the observation optical system, such as the above-mentioned conditional expressions.

In addition, the observation optical system according to the present invention includes the first optical system.
What is necessary is just to comprise the said reflection surface of a prism by mirror coating.

Further, the reflecting surface of the first prism is
A total reflection surface is configured to reflect when the light beam enters the reflection surface at an incident angle exceeding the critical angle for total reflection, and transmit the light beam when incident at an incident angle not exceeding the critical angle for total reflection. You may. Further, an optical member that transmits light may be provided on the reflection surface side of the first prism.

With this configuration, see-through observation is possible, and normal external observation is not hindered.
The head or face-mounted image display device using the observation optical system of the present invention can be continuously worn, and the trouble of attaching and detaching the head or face-mounted image display device can be saved.

It is also possible to observe a multiple image in which an external observation image and an image from the image display element are superimposed.

Incidentally, in order to enable see-through observation, the reflection surface of the first prism may be constituted by a half mirror.

An image display element, a main body in which any of the above-described observation optical systems according to the present invention is arranged as an eyepiece optical system, and an exit pupil of the observation optical system are held at an eyeball position of an observer. As described above, the head-mounted image display device can be configured to include the support member that supports the main body portion on the observer's head and the speaker member that provides sound to the observer's ear.

In this case, in the head mounted image display device, the main body includes an observation optical system for the right eye and an observation optical system for the left eye, and the speaker member includes a speaker member for the right ear. You may comprise so that it may have a speaker member for left ears.

In this head-mounted image display device, the speaker member may be constituted by an earphone.

In the optical system of the present invention, backward ray tracing is performed in the observation optical system, forward ray tracing is performed in the imaging optical system, and the light passes through the center of the object point, the pupil in the observation optical system, and the center of the aperture stop in the imaging optical system. If the ray that passes through and reaches the center of the image plane is the axial principal ray, the incident ray and the reflected ray of the axial principal ray are identical unless at least one reflecting surface is decentered with respect to the axial principal ray. And the axial chief ray is cut off in the optical system. As a result, an image is formed only by the light flux whose central portion is shielded, and the center becomes dark or the image is not formed at the center at all. Therefore, an eccentric prism is used as the prism used in the present invention.

When the reflecting surface with power is decentered with respect to the axial principal ray, at least one of the surfaces constituting the prism member used in the present invention is a rotationally asymmetric surface. Is desirable. Among them, it is particularly preferable that at least one reflecting surface of the prism member is a rotationally asymmetric surface in terms of aberration correction.

In order to bend the optical path and use the optical path of the common area redundantly, it is necessary to decenter the optical system. However, if the optical system is an eccentric optical system in order to bend the optical path in this manner, eccentric aberrations such as rotationally asymmetric distortion and rotationally asymmetric field curvature are generated. To correct this eccentric aberration, a rotationally asymmetric surface is used as described above.

The rotationally asymmetric surface used in the present invention is
It can be constituted by a plane-symmetric free-form surface having only one anamorphic surface, toric surface and symmetry surface. In addition,
Preferably, a free-form surface having only one plane of symmetry may be used.

In the present invention, in the observation optical system, the on-axis chief ray is traced by a ray that passes through the center of the exit pupil and reaches the center of the observation image forming member. Are defined by forward ray tracing with rays reaching the center of the image sensor through the center of the image sensor. Then, the optical axis defined by a straight line from the center of the exit pupil or the aperture stop to the center of the aperture stop and intersecting the second exit surface of the second prism is defined as the Z axis, and is orthogonal to the Z axis. In addition, an axis in the eccentric plane of each surface constituting the second prism is defined as a Y axis, and an axis orthogonal to the Z axis and orthogonal to the Y axis is defined as an X axis. The center of the exit pupil or the aperture stop is the origin of the coordinate system in the observation optical system or the imaging optical system of the present invention. Further, in the present invention, surface numbers are assigned by reverse ray tracing from the exit pupil to the observation image forming member as described above, or by forward ray tracing from the aperture stop to the image sensor, and the axial principal ray is emitted. The direction from the pupil to the observation image forming member or the direction from the aperture stop to the image sensor is the positive direction of the Z axis, the direction of the Y axis toward the observation image forming member or the direction of the Y axis toward the image sensor is the positive direction of the Y axis. The direction, the Y axis, the Z axis, and the direction of the X axis forming the right-handed system are defined as the positive direction of the X axis.

Here, the free-form surface used in the present invention is defined by the following equation (a). Note that the Z axis of the definition formula is the axis of the free-form surface.

[0096] Here, the first term of the equation (a) is a spherical term, and the second term is a free-form surface term.

In the spherical term, c: curvature of the vertex k: conic constant (conical constant) r = √ (X ² + Y ² ).

The free-form surface term is Here, C _j (j is an integer of 2 or more) is a coefficient, and j =
{(M + n) ² + m + 3n} / 2 + 1 (m and n are integers of 0 or more).

The free-form surface generally includes an XZ plane,
Although neither YZ plane has a plane of symmetry, in the present invention,
By setting all odd-order terms of X to 0, the YZ plane and
The free-form surface has only one parallel symmetry surface. this
Such a free-form surface is represented by, for example, C
_Two, C_Five, C₇, C₉, C₁₂, C₁₄, C₁₆, C₁₈,
C ₂₀, C_{twenty three}, C_{twenty five}, C₂₇, C₂₉, C₃₁, C₃₃, C₃₅・ ・
Can be achieved by setting the coefficient of each term to 0
It is possible.

By setting all odd-numbered terms of Y to 0, a free-form surface having only one symmetry plane parallel to the XZ plane is obtained. Such a free-form surface is, for example, C ₃ , C ₅ , C ₈ , C ₁₀ , C ₁₂ ,
_{C 14, C 17, C 19} , C 21, C 23, C 25, C 27, C 30, C
_32, the coefficient of each term of C _34, C ₃₆ · · · can be achieved by zero.

Further, any one of the directions of the above-mentioned symmetry plane is set as a symmetry plane, and the eccentricity in the corresponding direction, for example, YZ
The eccentricity of the optical system is set in the Y-axis direction with respect to the plane of symmetry parallel to the plane, and the eccentric direction of the optical system is set in the X-axis direction with respect to the plane of symmetry parallel to the XZ plane. This makes it possible to effectively correct rotationally asymmetric aberrations and improve productivity at the same time.

Further, the above-mentioned definition expression (a) is shown as one example as described above. In the present invention, by using a rotationally asymmetric surface having only one plane of symmetry, the rotation caused by eccentricity is achieved. It has the feature of correcting asymmetric aberrations and at the same time improving the manufacturability, but it goes without saying that the same effect can be obtained for any definition formula other than the above definition formula (a).

In the present invention, the shape of the reflecting surface provided on the prism member can be configured as a plane-symmetric free-form surface having only one plane of symmetry.

The shape of the anamorphic surface is defined by the following equation (b). In addition, it passes through the origin of the surface shape,
A straight line perpendicular to the optical surface is the axis of the anamorphic surface.

Z = (Cx · X ² + Cy · Y ² ) / [1+ {1− (1 + Kx) Cx ² · X ² − (1 + Ky) Cy ² · Y ² } ^1/2 ] + {Rn} (1-Pn) X ² + (1 + Pn) Y ² ｝ ^{(n + 1)} (b) Here, assuming that n = 4 (fourth-order term) as an example, the above equation (b) is, when expanded, the following equation ( c).

Z = (Cx · X ² + Cy · Y ² ) / [1+ {1− (1 + Kx) Cx ² · X ² − (1 + Ky) Cy ² · Y ² ｝ ^1/2 ] + R1} (1-P1) ^{X 2 + (1 + P1)} Y 2} 2 + R2 {(1-P2) X 2 + (1 + P2) Y 2} 3 + R3 {(1-P3) X 2 + (1 + P3) Y 2} 4 + R4 {(1-P4 ) X ² + (1 + P4) Y ² ｝ ⁵ (c) where Z is the amount of deviation of the surface shape from the tangent plane to the origin, Cx is the curvature in the X-axis direction, Cy is the curvature in the Y-axis direction, and Kx is X An axial conic coefficient, Ky is a Y-axial conic coefficient, Rn is a rotationally symmetric component of the spherical term, and Pn is a rotationally asymmetric component of the aspherical term. The radius of curvature Rx in the X-axis direction and the radius of curvature R in the Y-axis direction
y and the curvatures Cx, Cy have a relationship of Rx = 1 / Cx, Ry = 1 / Cy.

The toric surface includes an X toric surface and a Y toric surface, and the following expressions (d) and (e), respectively.
Defined by A straight line passing through the origin of the surface shape and perpendicular to the optical surface is the axis of the toric surface.

The X toric surface is defined by the following equation (d).

F (X) = Cx · X ² / [1+ {1− (1 + K) Cx ² · X ² ｝ ^1/2 ] + AX ⁴ + BX ⁶ + CX ⁸ + DX ¹⁰ ... Z = F (X ) + (1/2) Cy {Y ² + Z ² −F (X) ² } (d) The Y toric surface is defined by the following equation (e).

F (Y) = Cy · Y ² / [1+ {1− (1 + K) Cy ² · Y ² ｝ ^1/2 ] + AY ⁴ + BY ⁶ + CY ⁸ + DY ¹⁰ ... Z = F (Y ) + (1/2) Cx {X ² + Z ² −F (Y) ² } (e) where Z is the deviation of the surface shape from the tangent plane to the origin, Cx is the curvature in the X-axis direction, Cy Is a curvature in the Y-axis direction, K is a conic coefficient, and A, B, C, and D are aspherical coefficients. Note that X
Axial radius of curvature Rx, Y-axis radius of curvature Ry and curvature C
x and Cy have a relationship of Rx = 1 / Cx and Ry = 1 / Cy.

The hologram element includes a relief hologram and a volume hologram. Relief-type holograms have low incident angle selectivity and wavelength selectivity, and diffract light at a specific incident angle and wavelength to form an image as the required order light. It has the property that it is diffracted in a state where the efficiency is reduced, and forms an image as unnecessary-order light. On the other hand, volume holograms have high incidence angle selectivity and wavelength selectivity, diffract only light of a specific wavelength and incident angle to form an image as a required order light, and most other light is assumed to be a zero order light. It has the property of transmitting light and making it difficult to image unnecessary order light.

Therefore, if a reflection type volume hologram is used as the hologram element used in the present invention, occurrence of image blur due to unnecessary order light can be prevented, and a clear observation image can be obtained.

The volume hologram (HOE) as the hologram element in the present invention is defined as follows. FIG. 25 is a principle diagram for defining the HOE in the present invention.

First, the ray tracing of the wavelength λ that enters and exits the HOE surface is performed by using the optical path difference function Φ ₀ on the HOE surface defined with respect to the reference wavelength λ ₀ = HWL using the following equation ( f).

[0115] _{n d Q d × N = n} i Q i × N + m (λ / λ 0) ∇Ф 0 × N ··· (f) However, the normal vector of N is HOE plane, n _i (n _d) Is the refractive index on the incident side (exit side), and Q _i (Q _d ) is the incident (exit) vector (unit vector). Also, m = HO
R is the diffraction order of the emitted light.

The HOE is a two-point light source having a reference wavelength λ ₀ , that is, as shown in FIG. 25, a point P ₁ = (HX1, HY1,
HZ1) as a light source and a point P ₂ = (HX
2, HY2, HZ2) as a light source, is defined (defined) as follows: Φ ₀ = Φ ₀ ^2P = n ₂ · s ₂ · r ₂ -n ₁ · s ₁ · r It becomes ₁ . Here, r ₁ (r ₂ ) is a distance (> 0) from point P ₁ (point P ₂ ) to predetermined coordinates P on the HOE surface, and n ₁ (n
₂ ) is the point P of the medium in which the HOE is placed at the time of manufacture (at the time of definition).
₁ is the refractive index on the side where the point (point P ₂ ) is located, and s ₁ = HV
1, and s ₂ = HV2 are codes that take into account the traveling direction of light. This code is REA = + 1 when the light source is a divergent light source (real point light source), and VIR = −1 when the light source is a convergent light source (virtual point light source). As the definition of the HOE in the lens data, the refractive index n ₁ (n ₂ ) of the medium on which the HOE is placed at the time of manufacture (at the time of definition) is determined by the point P ₁ ( The refractive index on the side where the point P ₂ ) exists.

In the general case, the reference light and the object light when manufacturing the HOE are not necessarily spherical waves. The optical path difference function Φ ₀ of the HOE in this case is an additional phase term Φ ₀ represented by a polynomial.
^Poly (optical path difference function at the reference wavelength λ ₀ ) can be added and expressed by the following equation (g).

Φ ₀ = Φ ₀ ^2P + Φ ₀ ^Poly (g) where the polynomial is In general, j = {(m + n) ² + m + 3n} /
2 can be defined. Here, H _j is a coefficient of each term.

Further, for convenience of optical design, the optical path difference function Φ
₀And Φ₀= Φ₀ ^Poly HOE is defined only by an additional term, such as
You can also. For example, a two-point light source P₁(Point P_Two)
When matched, the optical path difference function Φ₀Component Φ due to interference of ₀ ^2PIs
Since it is zero, in this case it is practically an additional term (polynomial)
This is equivalent to displaying the optical path difference function only by using the function.

The above description regarding the HOE has been all given in the HOE.
This is for local coordinates with respect to the origin.

The following is an example of configuration parameters defining the HOE. Surface number Curvature radius Surface spacing Object surface ∞ ∞ 1 ∞ (aperture) 100 2 150 (HOE) -75 HOE HV1 (s ₁ ): REA (+1) HV ₂ (s ₂ ): VIR (-1) HOR (m): 1 HX1 = 0 HY1 = −3.40 × 10 ⁹ HZ1 = −3.40 × 10 ⁹ HX2 = 0 HY2 = 2.50 × 10 HZ2 = -7.04 × 10 HWL (λ ₀ ) = 544 H ₁ -1.39 × 10 ^-21 H ₂ -8.57 × 10 ^-5 H ₃ -1.50 × 10 ^-4 .

The principle of reflection, diffraction and transmission on the volume hologram surface used in the present invention will be described. The simulation of the diffraction efficiency is shown by simulating the diffraction efficiency of the S-polarized component light based on Kogelnik's theory. This simulation is for Example 1 described later, but the same applies to other examples.

In this embodiment, the center wavelengths for light of R, G and B bands are 630 nm and 520 nm, respectively, as the light source.
m, 470 nm LED light source using a narrow band filter, each band width narrowed to the center wavelength ± 5 nm to about 10 nm. For example, the diffraction efficiency of the G-band axial principal ray on the volume hologram surface. The calculation result of is shown.
Note that the calculation results are obtained when the reference refractive index is 1.5, the refractive index modulation is 0.05, and the thickness of the hologram element is 10 μm. The incident angle of the axial chief ray on the volume hologram surface is 4
FIGS. 26 and 27 show the diffraction efficiency when the reflection diffraction angle is 7.3 ° and the reflection diffraction angle is 46.9 °. FIG. 26 shows that the wavelength is 520n.
The diffraction efficiency (vertical axis) with respect to the incident angle (horizontal axis) of the on-axis principal ray of m is shown in FIG.
It is a graph which shows the diffraction efficiency (vertical axis) of the axial chief ray of 3 degrees, respectively.

FIG. 26 shows that a high diffraction efficiency of about 100% can be obtained near the incident angle of 47.3 °.
According to FIG. 27, it can be seen that good reflection / diffraction efficiency can be obtained in the wavelength range of about 520 nm ± 20 nm.
On the other hand, the light beam reflected by the reflecting surface of the first prism after the reflection diffraction enters the volume type volume hologram surface again,
At this time, the axial principal ray enters at an incident angle of 18.7 °. In this case, it can be seen from FIG. 26 that the light beam passes as it is because it falls outside the range of the angle selectivity of the volume hologram element having high diffraction efficiency and is low, close to 0%.

The same applies to the R band and the B band. Further, a switching hologram element using liquid crystal can be used as the hologram element.

[0126]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the observation optical system and the imaging optical system according to the present invention will be described.

Incidentally, the constituent parameters of the first to fifth embodiments will be described later. In each embodiment, for example, as shown in FIG. 1, the axial chief ray 2 is moved from the center of the exit pupil 1 (or the aperture stop 14) (the center of rotation of the observer's eyeball) to the second prism 4 and the second prism 4. One prism 3 is defined by a light beam reaching the center of the LCD 5 (or the image sensor 13) provided as an observation image forming member. Then, the optical axis of the axial principal ray 2 is defined by a straight line until it intersects the surface 4 ₁ of the exit pupil 1 side of the second prism 4 is Z-axis, perpendicular to the Z axis, and constituting the prism An axis within the eccentric plane of each surface to be defined is defined as a Y axis, and an axis orthogonal to the optical axis and orthogonal to the Y axis is defined as an X axis. The center of the exit pupil 1 (or the aperture stop 14) is set as the origin of this coordinate system. Then, the on-axis principal ray 2 is shifted from the exit pupil 1 (or the aperture stop 14) by LC
The direction leading to D5 (or the image sensor 13) is a positive Z-axis direction, the direction of the Y axis toward the LCD 5 (or the image sensor 13) is a positive Y-axis direction, and a Y-axis, a Z-axis and a right-handed system are configured. The direction of the X axis is defined as the positive direction of the X axis.

In the first to fifth embodiments, the first prism 3 and the second prism 4 are decentered in the YZ plane.
The only symmetrical plane of each rotationally asymmetric free-form surface provided in the first prism 3 and the second prism 4 is defined as a YZ plane.

For the eccentric surface, the amount of eccentricity from the center of the origin of the optical system to the top of the surface (X-axis direction, Y-axis direction, Z-axis direction)
The axial directions are X, Y, and Z, respectively, and the central axis of the surface (for the free-form surface, the Z-axis of the above-described formula (a), and for the toric surface, the above-described formulas (d) and (e)). X of Z axis)
The tilt angles (α, β, γ (°), respectively) about the axis, the Y axis, and the Z axis are given. In that case, α
The positive of β and β means counterclockwise with respect to the positive direction of each axis, and the positive of γ means clockwise with respect to the positive direction of Z axis. How to rotate α, β, γ of the central axis of the surface is
The center axis of the plane and its XYZ orthogonal coordinate system are first rotated α counterclockwise around the X axis, and then the center axis of the rotated plane is rotated counterclockwise around the Y axis of the new coordinate system. The coordinate system rotated once and the coordinate system rotated once are also rotated counterclockwise around the Y axis by β, and then the center axis of the twice rotated surface is changed to the Z axis of the new coordinate system of the new coordinate system. The clockwise rotation is γ.

Further, among the optical working surfaces constituting the optical system of each embodiment, when a specific surface and a subsequent surface constitute a coaxial optical system, a surface interval is given, and in addition, a spherical surface is provided. The radius of curvature, the refractive index of the medium, and the Abbe number are given according to conventional methods.

Further, the shape of the surface of the free-form surface used in the present invention is a free-form surface defined by the above equation (a), and the Z axis of the definition equation is the axis of the free-form surface.

As another definitional expression of the free-form surface, Ze
There is an rnik polynomial. The shape of this surface is defined by the following equation (h). The Z axis of the definition formula (h) is Zernik
e is the axis of the polynomial. The definition of a rotationally asymmetric surface is defined by polar coordinates of the height of the Z axis with respect to the XY plane, where R is XY
A in-plane distance from the Z axis, A is an azimuth around the Z axis, and can be represented by a rotation angle measured from the X axis.

X = R × cos (A) y = R × sin (A) Z = D_Two + D_ThreeRcos (A) + D_FourRsin (A) + D_FiveR^Two cos (2A) + D₆(R^Two-1) + D₇R^Two sin (2A) + D₈R^Threecos (3A) + D₉(3R^Three-2R) cos (A) + D_Ten(3R^Three-2R) sin (A) + D₁₁R^Threesin (3A) + D₁₂R^Fourcos (4A) + D₁₃(4R^Four-3R^Two) Cos (2A) + D₁₄(6R^Four-6R^Two+1) + D₁₅(4R^Four-3R^Two) Sin (2A) + D₁₆R^Foursin (4A) + D₁₇R^Fivecos (5A) + D₁₈(5R^Five-4R^Three) Cos (3A) + D₁₉(10R^Five-12R^Three+ 3R) cos (A) + D₂₀(10R^Five-12R^Three+ 3R) sin (A) + D_{twenty one}(5R^Five-4R^Three) Sin (3A) + D_{twenty two}R^Fivesin (5A) + D_{twenty three}R⁶cos (6A) + D_{twenty four}(6R⁶-5R^Four) Cos (4A) + D_{twenty five}(15R⁶-20R^Four+ 6R^Two) Cos (2A) + D₂₆(20R⁶-30R^Four+ 12R^Two-1) + D₂₇(15R⁶-20R^Four+ 6R^Two) Sin (2A) + D₂₈(6R⁶-5R^Four) Sin (4A) + D₂₉R⁶sin (6A) ··········· (h) where D_m(M is an integer of 2 or more) is a coefficient. What
To design an optical system symmetrical in the X-axis direction,
D_Four, D_Five, D₆, D_Ten, D₁₁, D₁₂, D₁₃, D₁₄, D
₂₀, D_{twenty one}, D_{twenty two}Use….

The shape of a free-form surface that is a rotationally asymmetric surface can also be defined by the following equation (i). The Z axis in the definition formula (i) is the axis of the rotationally asymmetric surface.

[0135] _{Z = Σ n Σ m C nm} X n Y nm ···· (i) where, n is 0~k of sigma _n is sigma, m of sigma _m is sigma is 0~n
Represents

In the first to fifth embodiments of the present invention, the surface shape is expressed by the free-form surface using the above equation (a), but the same applies to the use of the above equations (h) and (i). Needless to say, the effect of the invention can be obtained.

Examples 1 to 5 will be specifically described below. In these embodiments, an image display device using an observation optical system will be described.

FIGS. 1 to 5 show YZ sectional views including the optical axis of the observation optical system according to Examples 1 to 5 of the present invention.
The observation optical system according to each of the embodiments includes an LCD arranged as an image forming member for displaying an image observed by an observer on an image plane side.
5 and an exit pupil 1 formed at an observer's eyeball position (pupil plane) to observe an observation image formed by the image forming member.
Eyepiece optical member for guiding to

The eyepiece optical member comprises a first prism 3 and a second prism.
It is configured to include the prism 4.

In the description of each embodiment, in principle, the surface number of the optical system is traced in the order from the exit pupil 1 to the LCD 5 (reverse ray tracing), and the order of each surface in the first and second prisms is also reversed ray tracing. It will be expressed according to. Further, a light beam traveling in an optical path connecting the exit pupil 1 and the LCD 5 via the optical system is referred to as a first light beam.

The first prism 3 has a first incident surface 3 ₃ , with a transparent prism medium such as glass or plastic interposed therebetween.
The reflecting surface 3 _2, has a first exit surface 3 _1.

The second prism 4 has a second entrance surface 4 ₂ , with a transparent prism medium such as glass or plastic interposed therebetween.
And a second exit surface 4 _1.

The first prism 3 and the second prism 4 have a reflection type volume hologram (H
OE) 6 therebetween.

The prism medium of the first prism 3 and the prism medium of the second prism 4 are made of the same medium, such as glass or plastic.

[0145] The first incident surface 3 ₃ of the first prism 3, one embodiment also have a function of be disposed LCD5 side, to be incident on the first prism 3 passes through the light beam from the observation image A symmetrical surface that gives power to the light beam at the time of transmission is formed into a single free-form surface shape.

[0146] reflective surface 3 ₂ has a function to reflect light in the first prism 3, one embodiment also, the free positive curved surface of concave shape so as to provide power (here beam upon reflection curved surface ) Is formed. Further, the reflecting surface 3 _2,
Mirror coating is applied.

[0147] The first exit surface 3 _1, Example 1 has a curvature in the X-axis direction, with the cylindrical surface having no curvature in the Y-axis direction, the second embodiment does not have a curvature in the X-axis direction, Y Example 3 is a planar surface having a curvature in the axial direction, Example 3 is a flat surface, Example 4 is a toric surface having different curvatures in the X-axis and Y-axis directions, and Example 5 is a spherical surface. Has the function of emitting light rays to the outside of the first prism 3.

[0148] The second incident surface 4 ₂ of the second prism has an action which is disposed on the first prism 3 side, to be incident on the second prism 4 passes through the light beam emitted from the first prism 3 It is configured for each example the first exit surface 3 ₁ and substantially the same shape of the first prism 3.

[0149] The second exit surface 4 ₁ has a function to emit light outside the second prism 4, any of the embodiments also, the free curved plane of symmetry which gives power to the light upon transmission only one side And has the function of correcting at least one of rotationally asymmetric coma and astigmatism generated by the eyepiece optical member.

The first entrance surface 3 _{3 of} the first prism ₃ ,
The reflecting surface 3 _2, only one plane of symmetry of the second free-form surface of the exit surface 4 ₁ of the second prism 4, bent surfaces of the optical axis (Y-Z
(See FIGS. 1 to 5).

As described above, in the volume hologram 6, the first light beam has the first incident angle (for example, in the case of the first embodiment,
With respect to a light beam having a wavelength of 520 nm, the light beam is diffracted and reflected when incident at 47.3 °, and transmitted when the first light beam is incident at an angle other than the first incident angle. I have.

In the observation optical systems of Examples 1 to 5,
The first light beam emitted from the LCD 5 is incident on the first incident surface 3._ThreeTo
After transmitting and entering the inside of the first prism 3, the first exit
Face 3 ₁To the volume hologram 6 attached to the first
Incident at an angle of incidence. At this time, the incident first light flux
Indicates the number of reflection times close to 100% on the six surfaces of the volume hologram.
Diffraction with reflection efficiency, reflection surface 3_TwoReflection towards
Face 3_TwoIs reflected by the first exit surface 3₁Pasted on
Incident angles other than the first incident angle with respect to the volume hologram 6
Incident in degrees. The angle of incidence at this time is
From the angle selectivity of the diffraction efficiency with high diffraction efficiency
Therefore, the incident light of the first light beam is transmitted to the volume hologram 6.
And exits from the first prism 3. Then
One light beam is transmitted to the second incident surface 4 of the second prism 4.₁Through
The light enters the interior of the second prism 4 and is incident on the second exit surface 4._TwoThrough
The exit pupil 1 from the second prism 4
Guided to the side.

In Examples 1 to 5 of the present invention,
Although described as an observation optical system, an image pickup device 13 is arranged in place of the LCD 5 on the image plane of the observation optical system, and the brightness for narrowing the brightness of a light beam from an object on the pupil plane (the position of the exit pupil 1). By arranging the stop 14, it can be configured as an imaging optical system.

[0154] In this case, the first entrance surface 3 ₃ of the first prism 3, the light beam outside the first prism 3 acts as a surface to be emitted (4th exit surface), a first exit surface 3 _1, The light beam emitted from the second prism 4 acts as a surface (fourth incident surface) for entering the first prism 3. The second incidence surface 4 ₂ of the second prism 4, the second prism 4 rays outside act as a surface for injection (third exit surface), the second exit surface 4
₁ is a light beam from an object that has passed through the aperture stop 14
It functions as a surface (third incident surface) that enters the prism 4.

The present invention is configured as an image pickup optical system.
The light from the object that has passed through the aperture 14
Is the third incident surface 4 of the second prism 4₁Through the second
After entering the rhythm 4, the third exit surface of the second prism 4
4_TwoThe volume hologram 6 attached to the first
It is incident at an incident angle other than the incident angle. Angle of incidence at this time
The degree of diffraction of the volume hologram 6 has high diffraction efficiency.
The incident light of the first light beam is out of the angular selectivity of the efficiency.
Is transmitted through the volume hologram 6 and the second prism 4
And then the fourth entrance surface 3 of the first prism₁Through
Then, the light enters the first prism 3. After that, the luminous flux
Reflecting surface 3 of first prism 3_TwoReflecting surface 3 toward_TwoReflected in
And the fourth incident surface 3₁Volume holog pasted on
With respect to the ram 6, a substantially first incident angle (for example, in the case of the first embodiment)
In the case of a light having a wavelength of 520 nm, 47.3 °)
Incident. At this time, the incident first light beam is
According to the program 6, it is possible to rotate with a reflection diffraction efficiency close to 100%.
Fourth exit surface 3 which is folded and reflected _ThreeThrough the first prism
The beam 3 is emitted and guided to the image sensor 13.

In addition, volume holograms include R, G, B
These three layers are bonded together so that a color image can be observed.

In each of Examples 1 to 5, the image display element used was 0.55 inches in diagonal length, the aspect ratio was 4: 3, and the size was 8.448 mm in length × 11.2 in width.
64 mm. The central diopter is -1.0D,
Observation angle of view: horizontal full angle of view 30.0 °, vertical full angle of view 22.7
°, and the pupil diameter is φ4 mm. The eye relief was 28.34 mm in Example 1, 27.93 mm in Example 2,
Example 3 is 27.91 mm, Example 4 is 28.34 m
m, Example 5 is 27.95 mm.

Numerical data of each embodiment are shown below. In the table below, "FFS" is a free-form surface, "CYL" is a cylindrical surface, "HOE" is a reflection hologram surface, and "TOE".
“R” indicates a toric surface, and “RE” indicates a reflective surface.

Example 1 Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object plane ∞-1000.00 1 ∞ (pupil plane) Eccentricity (1) 2 FFS Eccentricity (2) 1.5254 56.2 3 CYL Eccentricity (3) 1.5254 56.2 4 FFS (RE) Eccentricity (4) 1.5254 56.2 5 CYL (HOE) Eccentricity (3) 1.5254 56.2 6 FFS Eccentricity (5) Image plane ∞ Eccentricity (6) CYL Rx -183.88 Ry ∞ FFS C ₄ 1.4081 × 10 ^-2 C ₆ 1.9480 _{^{× 10 -2 C 8 5.7152 × 10}} -4 C 10 3.1468 × 10 -4 C 11 -9.0005 × 10 -6 C 13 -5.2999 × 10 -5 C 15 -2.0707 × 10 -5 FFS C 4 -6.6649 × 10 - ³ C ₆ -3.7544 × 10 ^-3 C ₈ 1.2394 × 10 ^-4 C ₁₀ 2.2242 × 10 ^-5 C ₁₁ -3.2898 × 10 ^-6 C ₁₃ -1.4789 × 10 ^-5 C ₁₅ -5.7270 × 10 ^-6 FFS C ₄ -5.5913 × 10 ^-3 C ₆ -1.1475 × 10 ^-2 C ₈ -6.6952 × 10 ^-4 C ₁₀ 6.7 339 × 10 ^-5 C ₁₁ 9.2 151 × 10 ^-5 C ₁₃ 3.7627 × 10 ^-4 C ₁₅ 1.5673 × 10 ^-4 HOE HV1: REA HV2: REA HOR: 1 HX1: 0.0 HY1: 0.0 HZ1: 0.0 HX2: 0.0 HY2: 0.0 HZ2: 0.0 (first layer) HWL: 630 H ₂ 0.1033 × 10 ^-2 H ₃ -0.2160 × 10 ^-2 H ₅ -0.1062 × 10 ^-2 H ₇ -0.1201 × 10 ^-3 H ₉ -0.3 320 × 10 ^-4 H ₁₀ 0.6054 × 10 ^-5 H ₁₂ -0.6586 × 10 ^-6 H ₁₄ -0.2407 × 10 ^-6 H ₁₆ 0.5397 × 10 ^-6 H ₁₈ 0.5652 × 10 ^-8 H ₂₀ -0.1139 × 10 ^-7 H ₂₁ -0.9545 × 10 ^-8 H ₂₃ 0.2587 × 10 ^-7 H ₂₅ -0.2341 × 10 ^-8 H ₂₇ 0.5905 × 10 ^-10 (2nd layer) HWL: 520 H ₂ 0.7285 × 10 ^-3 H ₃ -0.1900 × 10 ^-2 H ₅ -0.9272 × 10 ^-3 H ₇ -0.1079 × 10 ^-3 H ₉ -0.3038 × 10 ^-4 H ₁₀ 0.5751 × 10 ^-5 H ₁₂ -0.1250 × 10 ^-5 H ₁₄ -0.8794 × 10 ^-7 H ₁₆ 0.5433 × 10 ^-6 H ₁₈ -0.2290 × 10 ^-7 H ₂₀ 0.3096 × 10 ^-7 H _{21 ^{-0.9701 × 10 -8 H 23 0.2835 ×}} 10 -7 H 25 -0.2596 × 10 -8 H 27 0.1819 × 10 -8 ( third _{layer) HWL: 470 H 2 0.4134 ×} 10 -3 H 3 -0.1746 × 10 - ² H ₅ -0.8496 × 10 ^-3 H ₇ -0.1006 × 10 ^-3 H ₉ -0.2702 × 10 ^-4 H ₁₀ 0.5553 × 10 ^-5 H ₁₂ -0.1524 × 10 ^-5 H ₁₄ 0.7510 × 10 ^-7 H ₁₆ 0.5495 × 10 ^-6 H ₁₈ -0.4000 × 10 ^-7 H ₂₀ 0.5038 × 10 ^-7 H ₂₁ -0.9397 × 10 ^-8 H ₂₃ 0.2966 × 10 ^-7 H ₂₅ -0.2949 × 10 ^-8 H ₂₇ 0.2580 × 10 ^-8 (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y -2.67 Z 28.34 α 10.37 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 4.54 Z 31.74 α 20.14 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -1.47 Z 39.62 α -12.73 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 11.09 Z 35.79 α 69.79 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 17.48 Z 38.23 α -116.96 β 0.00 γ 0.00 θ = 69.86 ° Dx / Rx = -0.0613 Dx / Ry = 0 Da / Ra = -0.0944 Db / Rb = 0.

Example 2 Surface number Curvature radius Surface spacing Eccentricity Refractive index Abbe number Object plane -100-1000.00 1 ∞ (pupil plane) Eccentricity (1) 2 FFS Eccentricity (2) 1.5254 56.2 3 CYL Eccentricity (3) 1.5254 56.2 4 FFS (RE) Eccentricity (4) 1.5254 56.2 5 CYL (HOE) Eccentricity (3) 1.5254 56.2 6 FFS Eccentricity (5) Image plane 偏 Eccentricity (6) CYL Rx ∞ Ry -167.81 FFS C ₄ 3.2852 × 10 ^-2 C ₆ 3.2975 _{^{× 10 -3 C 8 3.1981 × 10}} -4 C 10 4.3918 × 10 -4 C 11 -1.4812 × 10 -5 C 13 -5.4025 × 10 -5 C 15 3.8057 × 10 -5 FFS C 4 -6.4069 × 10 -4 C ₆ -1.0 330 × 10 ^-2 C ₈ 1.8977 × 10 ^-4 C ₁₀ 4.5314 × 10 ^-5 C ₁₁ -7.0 230 × 10 ^-6 C ₁₃ -1.6251 × 10 ^-5 C ₁₅ 4.6406 × 10 ^-6 FFS C ₄ -1.5137 × 10 ^-2 C ₆ 1.6463 × 10 ^-2 C ₈ -2.4620 × 10 ^-3 C ₁₀ 1.8 240 × 10 ^-4 C ₁₁ 1.5732 × 10 ^-4 C ₁₃ 3.2072 × 10 ^-4 C ₁₅ -2.8944 × 10 ^-4 HOE HV1 : REA HV2: REA HOR: 1 HX1: 0.0 HY1: 0.0 HZ1: 0.0 HX2: 0.0 HY2: 0.0 HZ2: 0.0 ( first _{layer) HWL: 630 H 2 0.5585 ×} 10 -2 H 3 _{^{-0.2727 × 10 -2 H 5 -0.2241 ×}} 10 -3 H 7 -0.1729 × 10 -3 H 9 0.2012 × 10 -4 H 10 0.4093 × 10 -5 H 12 -0.6315 × 10 -6 H 14 0.4235 × 10 - ⁶ H ₁₆ 0.4673 × 10 ^-6 H ₁₈ 0.4414 × 10 ^-6 H ₂₀ -0.3938 × 10 ^-6 H ₂₁ -0.1230 × 10 ^-7 H ₂₃ 0.3303 × 10 ^-7 H ₂₅ -0.7171 × 10 ^-9 H ₂₇ -0.1609 × 10 ^-7 (2nd layer) HWL: 520 H ₂ 0.4590 × 10 ^-2 H ₃ -0.2294 × 10 ^-2 H ₅ -0.9272 × 10 ^-3 H ₇ -0.1573 × 10 ^-3 H ₉ 0.2531 × 10 ^-4 H ₁₀ 0.5751 × 10 ^-5 H ₁₂ -0.9114 × 10 ^-6 H ₁₄ 0.1040 × 10 ^-5 H ₁₆ 0.5433 × 10 ^-6 H ₁₈ 0.3726 × 10 ^-6 H ₂₀ -0.3844 × 10 ^-6 H ₂₁ -0.9701 × 10 ^-8 H ₂₃ 0.3090 × 10 ^-7 H ₂₅ 0.1526 × 10 ^-9 H ₂₇ 0.1819 × 10 ^-8 (3rd layer) HWL: 470 H ₂ 0.3871 × 10 ^-2 H ₃ -0.2031 × 10 ^-2 H ₅ -0.2192 _{^{× 10 -3 H 7 -0.1416 × 10}} -3 H 9 0.2737 × 10 -4 H 10 0.2333 × 10 -5 H 12 -0.5933 × 10 -6 H 14 0.1284 × 10 -5 H 16 0.4896 × 10 -6 H 18 _{^{0.3413 × 10 -6 H 20 -0.3722 ×}} 10 -6 H 21 -0.3603 × 10 -8 H 23 0.2860 × 10 -7 H 25 -0.1499 × 10 -8 H 27 -0.1747 × 10 -7 eccentric (1) X 0.00 Y 0. 00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.36 Z 27.93 α 11.25 β 0.00 γ eccentricity (3) X 0.00 Y 3.67 Z 30.94 α 19.56 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -0.62 Z 38.24 α -13.13 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 11.01 Z 34.91 α 75.07 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 17.90 Z 36.47 α -115.50 β 0.00 γ 0.00 θ = 70.03 ° Dx / Rx = 0 Dx / Ry = −0.0707 Da / Ra = −0.1282 Db / Rb = 0.

Example 3 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface ∞ -1000.00 1 ∞ (pupil surface) Eccentricity (1) 2 FFS Eccentricity (2) 1.5254 56.2 3 ∞ Eccentricity (3) 1.5254 56.2 4 FFS (RE) Eccentricity (4) 1.5254 56.2 5 ∞ (HOE) Eccentricity (3) 1.5254 56.2 6 FFS Eccentricity (5) Image plane ∞ Eccentricity (6) FFS C ₄ 3.3501 × 10 ^-2 C ₆ 2.9604 × 10 ^-3 C ₈ 5.7973 × 10 ^-4 C ₁₀ 6.6754 × 10 ^-4 C ₁₁ -9.2202 × 10 ^-6 C ₁₃ -5.0913 × 10 ^-5 C ₁₅ 3.4518 × 10 ^-5 FFS C ₄ -2.5765 × 10 ^-4 C ₆ -8.8917 × 10 ^-3 C ₈ 2.4647 × 10 ^-4 C ₁₀ 3.8827 × 10 ^-5 C ₁₁ -6.6413 × 10 ^-6 C ₁₃ -1.3699 × 10 ^-5 C ₁₅ 6.8648 × 10 ^-6 FFS C ₄ -9.5889 × 10 ^-3 C _{6 ^{3.3124 × 10 -2 C 8 -3.5119 ×}} 10 -3 C 10 1.7859 × 10 -3 C 11 1.6079 × 10 -4 C 13 3.2884 × 10 -5 C 15 -3.2974 × 10 -4 HOE HV1: REA HV2: REA HOR : 1 HX1: 0.0 HY1: 0.0 HZ1: 0.0 HX2: 0.0 HY2: 0.0 HZ2: 0.0 ( first _{layer) HWL: 630 H 2 0.5015 ×} 10 -2 H 3 -0.2727 × 10 -2 H 5 -0.6845 × 10 - ⁴ H ₇ -0.12 53 × 10 ^-3 H ₉ 0.2997 × 10 ^-4 H ₁₀ 0.5917 × 10 ^-5 H ₁₂ -0.9083 × 10 ^-6 H ₁₄ 0.1669 × 10 ^-5 H ₁₆ 0.3649 × 10 ^-6 H ₁₈ -0.5739 × 10 ^-7 H ₂₀ -0.1921 × 10 ^-6 H ₂₁ -0.1067 × 10 ^-7 H ₂₃ 0.1352 × 10 ^-7 H ₂₅ -0.1290 × 10 ^-7 H ₂₇ -0.8941 × 10 ^-8 (2nd layer) HWL: 520 H ₂ 0.4085 × 10 ^-2 H ₃ -0.2327 × 10 ^-2 H ₅ -0.9226 × 10 ^-4 H ₇ -0.1099 × 10 ^-3 H ₉ 0.2933 × 10 ^-4 H ₁₀ 0.4942 × 10 ^-5 H ₁₂ -0.8760 × 10 ^-6 H ₁₄ 0.1990 × 10 ^-5 H ₁₆ 0.4349 × 10 ^-6 H ₁₈ -0.9 260 × 10 ^-7 H ₂₀ -0.1725 × 10 ^-6 H ₂₁ -0.5201 × 10 ^-8 H ₂₃ 0.1461 × 10 ^-7 H ₂₅ -0.1144 × 10 ^-7 H ₂₇ -0.1007 × 10 ^-7 (3rd layer) HWL: 470 H ₂ 0.3396 × 10 ^-2 H ₃ -0.2090 × 10 ^-2 H ₅ -0.1106 × 10 ^-3 H ₇ -0.9409 × 10 ^-4 H ^{_{9 0.2936 × 10 -4 H 10 0.4540}} × 10 -5 H 12 -0.4906 × 10 -6 H 14 0.2100 × 10 -5 H 16 0.4005 × 10 -6 H 18 -0.1097 × 10 -6 H 20 -0.1643 × 10 - ⁶ H ₂₁ -0.4518 × 10 ^-8 H ₂₃ 0.1283 × 10 ^-7 H ₂₅ -0.1245 × 10 ^-7 H ₂₇ -0.9771 × 10 ^-8 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y 0.37 Z 27.91 α 13.67 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 2.73 Z 30.67 α 16.01 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 0.09 Z 37.63 α -13.84 β 0.00 γ Eccentricity ( 5) X 0.00 Y 10.95 Z 35.87 α 80.36 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 18.32 Z 36.73 α -119.42 β 0.00 γ 0.00 θ = 73.99 ° Dx / Rx = 0 Dx / Ry = 0 Da / Ra = 0 Db / Rb = 0.

Example 4 Surface Number Curvature Radius Surface Distance Eccentricity Refractive Index Abbe Number Object Surface -100-1000.00 1 ∞ (pupil surface) Eccentricity (1) 2 FFS Eccentricity (2) 1.5254 56.2 3 TOR Eccentricity (3) 1.5254 56.2 4 FFS (RE) Eccentricity (4) 1.5254 56.2 5 TOR (HOE) Eccentricity (3) 1.5254 56.2 6 FFS Eccentricity (5) Image plane ∞ Eccentricity (6) TOR Rx -186.67 Ry-1921.54 FFS C ₄ 1.4572 × 10 ^-2 C ₆ 1.9424 × 10 ^-2 C ₈ 5.6 118 × 10 ^-4 C ₁₀ 3.0 191 × 10 ^-4 C ₁₁ -5.5671 × 10 ^-6 C ₁₃ -5.7474 × 10 ^-5 C ₁₅ -2.0993 × 10 ^-5 FFS C ₄ -6.5615 × 10 ^-3 C ₆ -3.9808 × 10 ^-3 C ₈ 1.1615 × 10 ^-4 C ₁₀ 2.5034 × 10 ^-5 C ₁₁ -2.4825 × 10 ^-6 C ₁₃ -1.5860 × 10 ^-5 C ₁₅ -5.8682 × 10 ^-6 FFS C ^{_{4 -5.3015 × 10 -3 C 6 -1.2565}} × 10 -2 C 8 -6.6936 × 10 -4 C 10 1.0147 × 10 -5 C 11 8.2407 × 10 -5 C 13 3.9328 × 10 -4 C 15 1.7057 × 10 - ^{4 HOE HV1: REA HV2: REA} HOR: 1 HX1: 0.0 HY1: 0.0 HZ1: 0.0 HX2: 0.0 HY2: 0.0 HZ2: 0.0 ( first _{layer) HWL: 630 H 2 0.1210 ×} 10 -2 ^{_{H 3 -0.2183 × 10 -2 H 5}} -0.1060 × 10 -2 H 7 -0.1201 × 10 -3 H 9 -0.3374 × 10 -4 H 10 0.5781 × 10 -5 H 12 -0.5260 × 10 -6 H 14 - 0.2197 × 10 ^-6 H ₁₆ 0.5362 × 10 ^-6 H ₁₈ 0.1622 × 10 ^-7 H ₂₀ -0.1139 × 10 ^-7 H ₂₁ -0.8656 × 10 ^-8 H ₂₃ 0.2598 × 10 ^-7 H ₂₅ -0.2152 × 10 ^-8 H ₂₇ 0.1856 × 10 ^-10 (2nd layer) HWL: 520 H ₂ 0.8868 × 10 ^-3 H ₃ -0.1923 × 10 ^-2 H ₅ -0.9251 × 10 ^-3 H ₇ -0.1079 × 10 ^-3 H ₉ -0.3086 _{^{× 10 -4 H 10 0.5549 × 10}} -5 H 12 -0.1148 × 10 -5 H 14 -0.7706 × 10 -7 H 16 0.5434 × 10 -6 H 18 -0.1750 × 10 -7 H 20 0.3104 × 10 -7 H ₂₁ -0.8797 × 10 ^-8 H ₂₃ 0.2840 × 10 ^-7 H ₂₅ -0.2596 × 10 ^-8 H ₂₇ 0.1818 × 10 ^-8 (3rd layer) HWL: 470 H ₂ 0.5610 × 10 ^-3 H ₃ -0.1773 × 10 ^{_{-2 H 5 -0.8460 × 10 -3 H}} 7 -0.1003 × 10 -3 H 9 -0.2778 × 10 -4 H 10 0.5545 × 10 -5 H 12 -0.1523 × 10 -5 H 14 0.7890 × 10 -7 H 16 0.5497 × 10 ^-6 H ₁₈ -0.3994 × 10 ^-7 H ₂₀ 0.5314 × 10 ^-7 H ₂₁ -0.9383 × 10 ^-8 H ₂₃ 0.2987 × 10 ^-7 H ₂₅ -0.2959 × 10 ^-8 H ₂₇ 0.2687 × 10 ^-8 Eccentricity (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (2) X 0.00 Y -2.59 Z 28.33 α 10.27 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 4.53 Z 31.72 α 20.19 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y -1.38 Z 39.58 α -12.78 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 11.08 Z 35.82 α 69.78 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 17.48 Z 38.14 α -116.76 β 0.00 γ 0.00 θ = 69.83 ° Dx / Rx = -0.0603 Dx / Ry = -0.0059 Da / Ra = -0.0928 Db / Rb = -0.0112.

Example 5 Surface number Curvature radius Surface distance Eccentricity Refractive index Abbe number Object plane ∞ -1000.00 1 ∞ (pupil plane) Eccentricity (1) 2 FFS Eccentricity (2) 1.5254 56.2 3 -2000 Eccentricity (3) 1.5254 56.2 4 FFS (RE) Eccentricity (4) 1.5254 56.2 5 -2000 (HOE) Eccentricity (3) 1.5254 56.2 6 FFS Eccentricity (5) Image plane ∞ Eccentricity (6) FFS C ₄ 3.2480 × 10 ^-2 C ₆ 2.9376 × 10 ^-3 C ₈ 6.3684 × 10 ^-4 C ₁₀ 6.6437 × 10 ^-4 C ₁₁ -1.1018 × 10 ^-5 C ₁₃ -4.7966 × 10 ^-5 C ₁₅ 3.1555 × 10 ^-5 FFS C ₄ -6.3947 × 10 ^-4 C ₆ -8.9236 _{^{× 10 -3 C 8 2.5164 × 10}} -4 C 10 5.4004 × 10 -5 C 11 -7.1084 × 10 -6 C 13 -1.3112 × 10 -5 C 15 6.0361 × 10 -6 FFS C 4 -9.3660 × 10 -3 C ₆ 3.1207 × 10 ^-2 C ₈ -3.4094 × 10 ^-3 C ₁₀ 1.6934 × 10 ^-3 C ₁₁ 1.5776 × 10 ^-4 C ₁₃ 7.0544 × 10 ^-5 C ₁₅ -3.2674 × 10 ^-4 HOE HV1: REA HV2: REA HOR: 1 HX1: 0.0 HY1 : 0.0 HZ1: 0.0 HX2: 0.0 HY2: 0.0 HZ2: 0.0 ( first _{layer) HWL: 630 H 2 5.8162 ×} 10 -3 H 3 -2.7701 × 10 -3 H 5 -7.1217 × 10 ^-5 H ₇ - 1.7079 × 10 ^-4 H ₉ 1.8 808 × 10 ^-5 H ₁₀ 6.2 670 × 10 ^-6 H ₁₂ -2.8904 × 10 ^-6 H ₁₄ 1.2124 × 10 ^-6 H ₁₆ 7.0035 × 10 ^-7 H ₁₈ 4.4748 × 10 ^-8 H ₂₀ -1.5532 × 10 ^-7 H ₂₁ -6.1624 × 10 ^-9 H ₂₃ 2.9 660 × 10 ^-8 H ₂₅ -7.0306 × 10 ^-9 H ₂₇ -7.1544 × 10 ^-9 (2nd layer) HWL: 520 H ₂ 4.8663 × 10 ^-3 H ₃ -2.3849 × 10 ^-3 H ₅ -9.0966 × 10 ^-5 H ₇ -1.5366 × 10 ^-4 H ₉ 1.8804 × 10 ^-5 H ₁₀ 5.3088 × 10 ^-6 H ₁₂ -2.7147 × 10 ^-6 H ₁₄ 1.4933 × 10 ^-6 H ₁₆ 7.4193 × 10 ^-7 H ₁₈ 5.0327 × 10 ^-9 H ₂₀ -1.3634 × 10 ^-7 H ₂₁ -1.0 116 × 10 ^-9 H ₂₃ 2.8 504 × 10 ^-8 H ₂₅ -5.8 172 × 10 ^-9 H ₂₇ -7.9636 × 10 ^-9 (third layer) HWL: 470 H ₂ 4.1797 × 10 ^-3 H ₃ -2.1530 × 10 ^-3 H ₅ -1.0820 × 10 ^-4 H ₇ -1.3803 × 10 ^-4 H ₉ 1.8955 _{^{× 10 -5 H 10 4.8880 × 10}} -6 H 12 -2.3165 × 10 -6 H 14 1.5907 × 10 -6 H 16 7.1219 × 10 -7 H 18 -1.3661 × 10 -8 H 20 -1.2815 × 10 -7 H ^{_{21 -2.4660 × 10 -10 H 23 2.7210}} × 10 -8 H 25 -7.2245 × 10 -9 H 27 -7.5296 × 10 -9 eccentric (1) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 polarized Heart (2) X 0.00 Y 0.00 Z 0.00 α 0.00 β 0.00 γ 0.00 Eccentricity (3) X 0.00 Y 2.75 Z 30.72 α 16.00 β 0.00 γ 0.00 Eccentricity (4) X 0.00 Y 0.11 Z 37.68 α -13.85 β 0.00 γ 0.00 Eccentricity (5) X 0.00 Y 10.97 Z 35.93 α 79.77 β 0.00 γ 0.00 Eccentricity (6) X 0.00 Y 18.33 Z 36.75 α -119.27 β 0.00 γ 0.00 θ = 73.92 ° Dx / Rx = −0.0094 Dx / Ry = -0.0094 Da / Ra = -0.0111 Db / Rb = -0.0087.

Next, representatively, FIG. 6 shows aberration diagrams representing image distortion of the first embodiment, and FIGS. 7 to 9 show aberration diagrams representing lateral aberrations in the respective wavelength regions of RGB. In these lateral aberration diagrams, the numbers in parentheses indicate (horizontal angle of view, vertical angle of view), and indicate the lateral aberration at that angle of view.

FIG. 10 is a sectional view taken along the line YZ including the optical axis of the observation optical system of the embodiment described above. The light transmitted through the hologram element 6 without being diffracted has an adverse effect as ghost light. FIG.

In the configuration of the above-described embodiment, even when the light beam enters the volume hologram 6 at the first incident angle, the light beam in the predetermined wavelength region is, for example, as shown in FIG. Instead of 100% diffracted reflection,
Unnecessary order light that is not very slightly diffracted and reflected is generated, and transmitted light may be generated.

[0167] Then, the transmitted light, for example, hit the light to the bottom surface 4 ₃ or the side surface of the ocular optical system shown in FIG. 11 (a direction perpendicular plane to the paper), the eye of the observer and the reflected light as a ghost light There is a risk of incidence.

[0168] Therefore, in the present invention, as shown in FIG. 10, in addition to the configuration shown in FIGS. 1-5, ghost light on the side surface and the bottom surface 4 ₃ sides of the first prism 3 and the second prism 4 A member having a property of absorbing light, such as black paint, is provided as a removing member by performing a paint process or the like. The ghost light removing member 15 is connected to the first prism 3
Rays in the incident surface 3 ₃ outside the effective diameter and, and light outside the effective diameter of the reflective surface 3 in ₂ of the first prism, the non-region or the like of the light beam effective diameter of the second exit surface 4 ₁ of the second prism 4 It is also desirable to provide it on a portion included in an optically active surface (a surface other than the optically active surface that transmits or reflects the first light flux in the first prism 3 and the second prism 4).

Next, the above-described observation optical system and imaging optical system according to the present invention include an observation device for observing an object image through an eyepiece, and an imaging device such as a CCD or a silver halide film which forms an object image and converts the image. It can be used as a photographing device that performs photographing by receiving light. Specifically, there are a microscope, a head-mounted image display device, an endoscope, a projector, a silver halide camera, a digital camera, a VTR camera, a personal computer with a built-in photographing device, and an information processing device such as a mobile phone. The embodiment will be exemplified below.

As an example, FIG. 12 shows a state in which the head-mounted image display device for binocular wearing is mounted on the head of the observer, and FIG. 13 is a sectional view thereof. In this configuration, an observation optical system according to the present invention is used as an eyepiece optical system 100 having an image display element 5 as shown in FIG. The portable image display device 102 such as a stationary or head-mounted image display device that can be observed with both eyes by being supported separately.

That is, in the image display device main body 102,
The observation optical system as described above is used as the eyepiece optical system 100, and the eyepiece optical system 100 is provided as a pair of left and right, and the image display element 5 composed of a liquid crystal display element is arranged on the image plane corresponding to them. Then, the image display device main body 102
As shown in FIG. 12, a temporal frame 103 as shown in FIG.
02 can be held in front of the observer's eyes. As shown in FIG. 13, the cover member between the second exit surface 4 ₁ of the exit pupil and the second prism 4 of the ocular optical system 100 9
1 is arranged. As the cover member 91, any of a parallel plane plate, a positive lens, and a negative lens may be used.

The speaker 1 is provided on the temporal frame 103.
04 is provided so that stereophonic sound can be heard together with image observation. Thus, the speaker 1
A playback device 106 such as a portable video cassette is connected to a display device main body 102 having a video playback device 105 via a video / audio transmission code 105.
06 is held at an arbitrary position such as a belt position as shown in the figure, so that video and audio can be enjoyed.
Reference numeral 107 in FIG. 12 denotes a control unit of the playback device 106 such as a switch and a volume. The image display device main body 10
2, electronic components such as a video processing circuit and an audio processing circuit are incorporated.

The cord 105 may have a jack at the tip so that it can be attached to an existing video deck or the like. Furthermore, it is connected to a tuner for TV radio wave reception,
It may be used for viewing, or may be connected to a computer to receive computer graphics images, message images from the computer, and the like. Also, in order to reject an obstructive code, an antenna may be connected to receive an external signal by radio waves.

Further, the observation optical system according to the present invention may be used in a head mounted image display device for one eye in which an eyepiece optical system is disposed in front of one of the right and left eyes. FIG. 14 shows a state in which the image display device for one eye is mounted on the head of the observer (in this case, mounted on the left eye). In this configuration, a display device main body 102 having one set of an eyepiece optical system 100 having an image display element 5 is attached to a front frame 108 at a position in front of a corresponding eye, and is continuously connected to the front frame 108 from side to side. A temporal frame 103 as shown is provided, so that the display device main body 102 can be held in front of one eye of the observer. Other configurations are the same as those in FIG. 12, and a description thereof will be omitted.

FIGS. 15 to 17 are conceptual diagrams of a configuration in which the main components of the imaging optical system according to the present invention are incorporated in the objective optical system of the finder section of the electronic camera. 15 is a front perspective view showing the appearance of the electronic camera 40, FIG. 16 is a rear perspective view of the same, and FIG. 17 is a sectional view showing the configuration of the electronic camera 40.

In this case, the electronic camera 40 includes a photographing optical system 41 having a photographing optical path 42, a finder optical system 43 having a finder optical path 44, and a shutter button 4.
5, including a flash 46, a liquid crystal display monitor 47, etc.
When the shutter button 45 disposed on the upper part of the camera 40 is pressed, the photographing is performed through the photographing objective optical system 48 in conjunction therewith. An object image formed by the photographing objective optical system 48 is formed on the imaging surface 50 of the CCD 49 via a filter 51 such as a low-pass filter or an infrared cut filter.

The object image received by the CCD 49 is displayed as an electronic image on the liquid crystal display monitor 47 provided on the back of the camera via the processing means 52. In addition, a recording element 61 is disposed in the processing means 52, and can record a captured electronic image. Note that this recording element 6
1 may be provided separately from the processing means 52, or may be configured to perform recording and writing electronically using a floppy (registered trademark) disk or the like. Further, the camera may be configured as a silver halide camera in which a silver halide film is arranged instead of the CCD 49.

Further, on the finder optical path 44,
A finder objective optical system 53 is provided, and the finder objective optical system 53 includes a cover lens 54.
A positive lens group 57 whose position can be adjusted in the optical axis direction for focusing, a brightness stop 14, a first prism 3 and a second prism 4. The cover lens 54 used as a cover member is a lens group having a negative power, and has an increased angle of view. The first
The prism 3 is the first prism 3 according to the first to fifth embodiments of the present invention.
In addition to the configuration, the diffracted and reflected light from the hologram 6 provided in the fourth entrance surface 3 ₁ has a reflecting surface 3 ₄ in the optical path to the fourth exit surface 3 _3. The object image formed on the image plane 90 by the finder objective optical system 53 is formed on a field frame of a Porro prism 55 which is an image erecting member.

Incidentally, the field of view of the Porro prism 55
First reflection surface 56₁And the second reflecting surface 56 _TwoTo separate between
It is located between them. Note that the Porro prism 55 is
1 reflection surface 56₁To the fourth reflecting surface 56_FourIt becomes. This polo
Behind the prism 55, the erect image is formed by the observer.
An eyepiece optical system 59 for guiding to the eyeball E is arranged.

In the camera 40 configured as described above, the finder objective optical system 53 can be configured with a small number of optical members, high performance and low cost can be realized, and the optical path itself of the objective optical system 53 can be bent. Therefore, the degree of freedom of arrangement inside the camera increases, which is advantageous in design.

Although the configuration of the photographing objective optical system 48 has not been mentioned in the configuration of FIG. 17, the photographing objective optical system 48 is not limited to the refraction type coaxial optical system, but may be of the present invention. Of course, it is also possible to use any type of imaging optical system including two prisms 3 and 4 as shown in the first to fifth embodiments.

Further, the eyepiece optical system 59 is used in the first embodiment of the present invention.
It may be configured using any type of eyepiece optical member composed of two prisms 3 and 4 as shown in FIGS.

FIG. 18 is a conceptual diagram showing a configuration in which the imaging optical system of the present invention is incorporated in the objective optical system 48 of the photographing section of the electronic camera 40, and the observation optical system of the present invention is incorporated in the eyepiece optical system 59 of the electronic camera 40. The figure is shown. In the case of this example, the imaging optical path 42
The photographing objective optical system 48 disposed above is composed of a cover member 65 composed of a positive lens and any type of imaging optical system composed of two prisms 3 and 4 as shown in the first to fifth embodiments of the present invention. Become. Then, the first prism 3 and the CCD
A filter 51 such as a low-pass filter or an infrared cut filter is disposed between the CCD 49 and the object image formed by the objective optical system 48 for imaging. The object image received by the CCD 49 is passed through a processing unit 52 to a liquid crystal display (LC).
D) Displayed on 60 as an electronic image. The processing unit 52 also controls a recording unit 61 that records an object image captured by the CCD 49 as electronic information. LCD6
The image displayed at 0 is guided to the observer's eyeball E via the eyepiece optical system 59.

This eyepiece optical system 59 is used in Embodiment 1 of the present invention.
The decentered prism optical systems 3 and 4 having the same configuration as the observation optical system shown in FIGS. 1 to 2 and a cover lens 91 arranged on the exit pupil side thereof. A backlight 92 for illuminating the LCD 60 is provided behind the LCD 60. The objective optical system for photographing 48 may include another lens (positive lens, negative lens) on the object side or image side of the two prisms 3 and 4 as a component thereof.

In the camera 40 thus configured, the photographing objective optical system 48 and the eyepiece optical system 59 can be composed of a small number of optical members, so that high performance and low cost can be realized, and the entire optical system is coplanar. The thickness in the direction perpendicular to the arrangement plane can be reduced.

In this example, a positive lens is disposed as the cover member 65 of the photographing objective optical system 48, but a negative lens or a plane parallel plate may be used.

Here, without providing the cover member, the surface of the imaging optical system according to the present invention which is arranged closest to the object can be used also as the cover member. In this example, the surface of the most object side is the third incidence surface 4 ₁ of the second prism 4. However, since the incidence surface 4 ₁ is decentered with respect to the optical axis,
If this surface is placed in front of the camera, when viewed from the subject side, it is illusioned that the shooting center of the camera 40 is shifted from itself. You usually feel that you are doing that.) Therefore, when the surface closest to the object side of the imaging optical system is an eccentric surface as in the present example, providing the cover member 65 (or the cover lens 54) may cause an uncomfortable feeling when viewed from the subject side. Without receiving
It is desirable to be able to receive images with the same feeling as an existing camera.

Next, FIG. 19 shows an image pickup optical system according to the present invention as an objective optical system 82 of an observation system of an electronic endoscope, and an observation optical system according to the present invention as an eyepiece optical system 87 of an observation system of an electronic endoscope. FIG. In the case of this example, the objective optical system 82 and the eyepiece optical system 87 of the observation system use optical systems having substantially the same form as those of the first to fifth embodiments. This electronic endoscope is
As shown in FIG. 19A, an electronic endoscope 71, a light source device 72 for supplying illumination light, a video processor 73 for performing signal processing corresponding to the electronic endoscope 71, and a video processor 73 A monitor 74 for displaying the output video signal, a VTR deck 75 and a video disk 76 connected to the video processor 73 for recording the video signal and the like, a video printer 77 for printing out the video signal as video, 19B, the distal end portion 80 of the insertion portion 79 of the electronic endoscope 71 and the eyepiece portion 81 thereof are arranged as shown in FIG. It is configured as shown.

The light beam illuminated from the light source device 72 passes through the light guide fiber bundle 88 and the illumination objective optical system 8.
9 illuminates the observation site. Then, light from this observation site is formed as an object image by the observation objective optical system 82 via the cover member 85. This object image is formed on the imaging surface of the CCD 84 via a filter 83 such as a low-pass filter or an infrared cut filter. Further, this object image is converted into a video signal by the CCD 84, and the video signal is directly displayed on the monitor 74 by the video processor 73 shown in FIG.
The video is recorded in the printer and printed out from the video printer 77 as a video. The image is displayed on the image display element 5 (FIG. 13) of the HMD 78 and displayed to the wearer of the HMD 78. At the same time, the video signal converted by the CCD 84 is displayed as an electronic image on the liquid crystal display element (LCD) 86 of the eyepiece section 81 via the image signal transmission means 93, and the displayed image is transmitted from the observation optical system of the present invention. Through the eyepiece optical system 87.

The endoscope thus configured can be configured with a small number of optical members, and can realize high performance and low cost. In addition, since the objective optical system 80 is arranged in the longitudinal direction of the endoscope,
The above effect can be obtained without inhibiting the reduction in diameter.

The endoscope thus configured can be configured with a small number of optical members, and can realize high performance and low cost. In addition, since the objective optical system 80 is arranged in the long axis direction of the endoscope,
The above effect can be obtained without inhibiting the reduction in diameter.

Next, FIGS. 20 to 22 are conceptual diagrams showing a configuration in which the imaging optical system of the present invention is incorporated in a personal computer which is an example of an information processing apparatus.

FIG. 20 is a front perspective view of the personal computer 300 with the cover opened, and FIG. 21 is a photographing optical system 30 of the personal computer 300.
3 and FIG. 22 is a side view of the state of FIG. As shown in FIGS. 20 to 22, a personal computer 300 is provided with a keyboard 301 for a processor to input information from outside.
And information processing means and recording means (not shown), a monitor 302 for displaying information to the operator, and a photographic optical system 303 for taking an image of the operator and surroundings. Here, the monitor 302 includes a transmissive liquid crystal display element that illuminates from the back with a backlight (not shown), a reflective liquid crystal display element that reflects and displays light from the front,
It may be an RT display or the like. Although the photographing optical system 303 is built in the upper right of the monitor 302 in the drawing, the position is not limited to this, and may be anywhere around the monitor 302 or around the keyboard 301.

The photographing optical system 303 includes a photographing optical path 304
Above, the objective optical system 200 including the imaging optical system of the present invention
And an image sensor chip 204 for receiving an image. These are built in the personal computer 300.

Here, an IR cut filter 203 is additionally attached on the image pickup device chip 204 to be integrally formed as an image pickup unit 206, and the objective optical system 20
Since the lens frame 201 can be fitted and attached to the rear end of the lens frame 201 with a single touch, the centering of the objective optical system 200 and the imaging element chip 204 and the adjustment of the surface interval are not required, and assembly is simplified. I have. Further, a cover glass 202 for protecting the objective optical system 200 is disposed at the tip of the lens frame 201.

The object image received by the image pickup device chip 204 is input to the processing means of the personal computer 300 via the terminal 205 and is displayed on the monitor 302 as an electronic image. The photographed image 305 of the person is shown. Also, this image 305
It can be displayed on a personal computer of a communication partner from a remote place via the processing means, the Internet or a telephone.

Next, a telephone, as another example of the information processing apparatus,
In particular, FIG. 23 shows an example in which the imaging optical system of the present invention is incorporated in a portable telephone which is particularly portable.

FIG. 23A is a front view of a mobile phone 400,
FIG. 23B is a side view, and FIG.
5 is a sectional view of FIG. As shown in FIGS. 23A to 23C, the mobile phone 400 includes a microphone unit 401 for inputting the voice of the operator as information, a speaker unit 402 for outputting the voice of the other party, and information for the operator. Input dial 4 for inputting
03, a monitor 404 for displaying information such as a photographed image of the operator himself or the other party and a telephone number, and a photographing optical system 405.
And an antenna 406 for transmitting and receiving communication radio waves, and processing means (not shown) for processing image information, communication information, input signals, and the like. Here, the monitor 404
Is a liquid crystal display element. In addition, in the drawings, the arrangement position of each component is not particularly limited to these. This photographing optical system 405
Denotes an imaging optical system 200 of the present invention disposed on the imaging optical path 407, and an imaging element chip 204 for receiving an image.
And These are built into the mobile phone 400.

Here, an IR cut filter 203 is additionally attached on the image sensor chip 204 to be integrally formed as an image pickup unit 206, and the objective optical system 20
Since the lens frame 201 can be fitted and attached to the rear end of the lens frame 201 with a single touch, the centering of the objective optical system 200 and the imaging element chip 204 and the adjustment of the surface interval are not required, and assembly is simplified. I have. Further, a cover glass 202 for protecting the objective optical system 200 is disposed at the tip of the lens frame 201.

The object image received by the image sensor chip 204 is input to processing means (not shown) via a terminal 205, and is sent to the monitor 404 as an electronic image, to the monitor of a communication partner, or to both. Is displayed. When transmitting an image to a communication partner, the processing means includes a signal processing function of converting information of an object image received by the image sensor chip 62 into a signal that can be transmitted.

Next, FIG. 28 shows a preferred configuration when a diffraction element such as a volume hologram is provided in the prism constituting the optical system according to the present invention. In the figure, eccentric prism P
Reference numerals 1 and P2 denote a first prism 3 and a second prism 4, respectively, included in the observation optical system or the imaging optical system of the present invention.
Now, when the image plane C (for example, the display surface of the image display device 5 and the imaging surface of the imaging device 13) forms a square as shown in the figure, the 1-1 surface of the eccentric prism P1 (the 1st surface of the first prism 3). the 2-2 face (the plane of symmetry D when the second second exit surface 4 ₁ of the prism 4) are formed in plane-symmetry free-form surface of the first entrance surface 3 ₃₎ or decentered prism P2 is, the image plane C Is desirably arranged so as to be parallel to at least one of the four sides forming the image in order to form a beautiful image.

Further, when this image plane C has four interior angles, such as a square and a rectangle, each formed at approximately 90 °, the plane of symmetry D of the plane-symmetric free-form surface becomes parallel to the image plane C. It is preferable that the image plane C is arranged parallel to two sides and coincides with a position where the image plane C is symmetrical left and right or up and down. With such a configuration, it is easy to obtain the accuracy of assembling when assembling into the device, which is effective for mass production.

Further, the 1-1 surface (the first entrance surface 3 _{3 of} the first prism 3) and the 1-2 surface (the first exit of the first prism 3) which are the optical surfaces constituting the decentered prisms P1 and P2. Face 3
_1), the 1-3 face (reflecting surface 3 ₂ of the first prism 3), the 2-1 face (second incidence surface 4 ₂ of the second prism 4), second-
When a plurality of surfaces or all the surfaces of the two surfaces (the second exit surface 4 _{1 of} the second prism 4) or the like are plane-symmetric free-form surfaces, the plurality of surfaces or the symmetric surfaces of all the surfaces are the same plane D. It is desirable from the viewpoint of both design and aberration performance to be configured to be disposed on the optical axis. It is desirable that the relationship between the symmetry plane D and the power plane of the diffraction element 6 be the same as described above.

Although the observation optical system, the imaging optical system, and the apparatus using the same according to the present invention have been described based on the embodiments, the present invention is not limited to these embodiments and can be variously modified.

[0205]

As described above, according to the present invention, it is possible to observe a bright display image and capture a bright object image, which is suitable for use in a portable telephone, a portable information terminal, and a head-mounted virtual image observation device. Easy to assemble, resistant to shocks such as vibration,
It is possible to provide a light-weight, compact, and well-corrected aberration-corrected observation optical system, an apparatus using the same, an imaging optical system, and an apparatus using the same.

[Brief description of the drawings]

FIG. 1 is a view showing Y including an optical axis of an optical system according to a first embodiment of the present invention.
It is -Z sectional drawing.

FIG. 2 is a view showing Y including an optical axis of an optical system according to a second embodiment of the present invention.
It is -Z sectional drawing.

FIG. 3 is a view showing Y including an optical axis of an optical system according to a third embodiment of the present invention.
It is -Z sectional drawing.

FIG. 4 is a view showing Y including an optical axis of an optical system according to a fourth embodiment of the present invention.
It is -Z sectional drawing.

FIG. 5 is a diagram illustrating Y including an optical axis of an optical system according to a fifth embodiment of the present invention.
It is -Z sectional drawing.

FIG. 6 is an aberration diagram illustrating image distortion of the first embodiment.

FIG. 7 is an aberration diagram illustrating an R band (red band) lateral aberration in the first embodiment.

FIG. 8 is an aberration diagram illustrating a lateral aberration in a G band (green band) according to the first embodiment.

FIG. 9 is an aberration diagram illustrating a lateral aberration in a B band (blue band) according to the first exemplary embodiment.

FIG. 10 is a YZ cross-sectional view including an optical axis of an observation optical system having a configuration provided with a ghost light removing member.

FIG. 11 is an explanatory diagram showing that light transmitted through the hologram element without being diffracted has an adverse effect as ghost light.

FIG. 12 is a diagram showing a state in which a head-mounted binocular image display device using the observation optical system of the present invention is mounted on the head of an observer.

FIG. 13 is a sectional view of FIG.

FIG. 14 is a diagram showing a state in which a head-mounted image display device for one eye mounting using the observation optical system of the present invention is mounted on the head of an observer.

FIG. 15 is a front perspective view showing the appearance of an electronic camera to which the imaging optical system and the observation optical system of the present invention are applied.

16 is a rear perspective view of the electronic camera of FIG.

17 is a cross-sectional view illustrating one configuration of the electronic camera in FIG.

FIG. 18 is a conceptual diagram of another electronic camera to which the imaging optical system and the observation optical system of the present invention are applied.

FIG. 19 is a conceptual diagram of an electronic endoscope to which the imaging optical system and the observation optical system of the present invention are applied.

FIG. 20 is a front perspective view of a personal computer in which the imaging optical system of the present invention is incorporated as an objective optical system with a cover opened.

FIG. 21 is a sectional view of a photographic optical system of a personal computer.

FIG. 22 is a side view of the state shown in FIG. 20;

23A and 23B are a front view, a side view, and a cross-sectional view of a mobile phone in which the imaging optical system of the present invention is incorporated as an objective optical system.

FIG. 24 is a diagram for describing the definition of an angle θ.

FIG. 25 is a principle diagram for defining a HOE in the present invention.

FIG. 26 shows a case where the volume hologram having the configuration of the present invention has a wavelength of 5;
It is a graph which shows the diffraction efficiency with respect to the incident angle of an on-axis principal ray of 20 nm.

FIG. 27 is a graph showing the diffraction efficiency of an axial chief ray having an incident angle of 47.3 ° with respect to the wavelength of the volume hologram having the configuration of the present invention.

FIG. 28 shows a prism constituting an optical system according to the present invention,
FIG. 3 is a diagram illustrating a preferred configuration when OEs are arranged.

FIG. 29 is a diagram for explaining two types of power when a hologram element is provided on a spherical substrate member;
(A) is a front view, (b) is a side view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Exit pupil 2 ... On-axis chief ray 3 ... 1st prism 3 ₁ ... 1st exit surface (4th entrance surface) 3 ₂ ... Reflection surface 3 ₃ ... 1st entrance surface (4th exit surface) 4 ... 2nd prism 4 ₁ ... second exit surface (third incidence surface) 4 ₂ ... second entrance surface (third exit surface) 4 ₃ ... bottom 5 ... LCD 6 ... volume hologram 13 ... image sensor 14 ... aperture stop 15 ... Ghost light removing member 40 Camera 41 Imaging optical system 42 Imaging optical path 43 Finder optical system 44 Finder optical path 45 Shutter 46 Flash 47 Liquid crystal display monitor 48 Object imaging optical system 49 CCD 50 Imaging surface 51 Filter 52 Processing means 53 Objective optical system for viewfinder 54 Negative lens group 55 Porro prism 56 _{1 to} 56 ₄ First to fourth reflecting surfaces 57 Lens group 59 Eyepiece optical system 60 Liquid crystal display Elementary Child (LCD) 61 Recording element 65 Cover member 71 Electronic endoscope 72 Light source device 73 Video processor 74 Monitor 75 VTR deck 76 Video disk 77 Video printer 78 Head-mounted image display device (HMD) 79 insertion part 80 tip part 81 eyepiece 82 observation objective optical system 83 filter 84 CCD 85 cover member 86 liquid crystal display (LCD) 87 eyepiece optical system 88 light guide Fiber bundle 89 Illuminating objective optical system 90 Image forming surface 91 Cover member 92 Backlight 93 Image signal conducting means 100 Eyepiece optical system 102 Image display device (main body) 103 Temporal frame 104 Speaker 105: video / audio transmission code 106: playback device 107: adjusting unit 108: previous frame 200: objective optical system 201 mirror frame 202 cover glass 203 IR cut filter 204 imaging element chip 205 terminal 206 imaging unit 300 personal computer 301 keyboard 302 monitor 303 imaging optical system 304 imaging optical path 305 image 400 mobile phone 401 microphone unit 402 speaker unit 403 input dial 404 monitor 405 photographic optical system 406 antenna 407 photographic optical path P1, P2 eccentric prism C image plane D plane symmetric free-form symmetric plane E observer Eyeball

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Tetsuhide Takeyama 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. No. 1 Dai Nippon Printing Co., Ltd. F term (reference) 2H087 KA00 KA03 LA12 NA02 NA14 RA32 RA34 RA41 RA42 RA46 TA01 TA04 TA06 UA01

Claims (29)

[Claims] 1. An observation image forming member for forming an observation image observed by an observer, and an eyepiece optical member for guiding an observation image formed by the observation image forming member to an exit pupil formed at an observer's eyeball position. In the observation optical system, the eyepiece optical member includes at least a first prism member and a second prism member, and the first prism has at least a first prism medium interposed therebetween, and has A first incident surface that allows light to enter the first prism, a reflective surface that reflects light within the first prism, and a first exit surface that emits light outside the first prism; A second prism has at least a second incident surface for interposing a second prism medium between the first prism and a light beam emitted from the first prism, and emits a light beam outside the second prism. And a second exit surface, wherein the first prism and the second prism are arranged so as to be joined to each other with a hologram element interposed between the first exit surface and the second entrance surface. The reflecting surface of the first prism is formed into a concave curved surface that gives a positive power to a light ray when reflected, and the first exit surface and the second incident surface are formed from a flat surface or a cylindrical surface. An observation optical system characterized by: 2. An observation image forming member for forming an observation image to be observed by an observer, and an eyepiece optical member for guiding an observation image formed by the observation image forming member to an exit pupil formed at an observer's eyeball position. In the observation optical system, the eyepiece optical member includes at least a first prism member and a second prism member, and the first prism has at least a first prism medium interposed therebetween, and has A first incident surface that allows light to enter the first prism, a reflective surface that reflects light within the first prism, and a first exit surface that emits light outside the first prism; A second prism has at least a second incident surface for interposing a second prism medium between the first prism and a light beam emitted from the first prism, and emits a light beam outside the second prism. And a second exit surface, wherein the first prism and the second prism are arranged so as to be joined to each other with a hologram element interposed between the first exit surface and the second entrance surface. The reflection surface of the first prism is formed into a concave curved surface that gives a positive power to a light ray when reflected, and the first exit surface and the second entrance surface satisfy a next condition, or An observation optical system characterized by being formed from a toric surface. -2.0 <Da / Ra <2.0 (2) -0.05 <Db / Rb <0.05 (3) where Ra and Da are the curvatures on the axis having the larger curvature. Rb and Db are the radius of curvature and the outer diameter of the axis with the smaller curvature. 3. The method according to claim 2, wherein the first incidence surface of the first prism is
The light emitting device according to claim 1, wherein the second prism has a curved surface shape that gives power to the light beam when transmitted, and the second exit surface of the second prism has a curved surface shape that gives power to the light beam when transmitted. 3. The observation optical system according to 1 or 2. 4. The observation optical system according to claim 1, wherein the first prism medium and the second prism medium are formed of the same kind of medium. 5. The surface shape of a first exit surface of the first prism and the surface shape of a second incident surface of the second prism are substantially the same. 5. The observation optical system according to any one of items 1 to 4. 6. A ghost light removing member that prevents ghost light from entering an eyeball of an observer on a non-optically active surface other than an optically active surface of the first prism and the second prism that transmits or reflects light rays. The observation optical system according to any one of claims 1 to 5, further comprising: 7. The observation optical system according to claim 1, wherein a surface shape of the first incident surface of the first prism is a rotationally asymmetric curved surface shape. 8. The rotationally asymmetric curved surface shape includes a free-form surface having only one symmetrical surface, and the only symmetrical surface coincides with a folded surface of the optical axis (YZ plane). The observation optical system according to claim 7, wherein: 9. The hologram element according to claim 1, wherein the hologram element is configured to correct the chromatic aberration of magnification of both the rotationally symmetric component and the rotationally asymmetric component by reflecting and diffracting the light beam. The observation optical system as described. 10. An angle formed between a tangent plane at a position where an on-axis principal ray intersects a substrate surface of the hologram element and an on-axis principal ray from the surface of the observation optical system closest to the exit pupil to the exit pupil. 10. The observation optical system according to claim 1, wherein the following conditional expression (1) is satisfied: 45 ° <θ <85 ° (1) 11. A surface shape of the second exit surface of the second prism has an action of correcting at least one of rotationally asymmetric coma and astigmatism generated by the eyepiece optical member. The observation optical system according to claim 1, wherein the observation optical system is configured to have a curved surface shape that is rotationally asymmetric. 12. The rotationally asymmetric curved surface shape includes a free-form surface having only one symmetrical surface, and the only symmetrical surface coincides with a folded surface of the optical axis (YZ plane). The observation optical system according to claim 11, wherein: 13. A folding plane of the optical axis is a YZ plane,
The direction of the axial chief ray from the exit pupil to the surface closest to the exit pupil of the observation optical system is orthogonal to the Z-axis direction and the Z-axis, and the eccentric direction of the optical system is the Y-axis direction, and the X-axis and the Z-axis are orthogonal to the right hand. The axis constituting the coordinate system is the Y axis, the length of the observation image forming member in the X axis direction is Dx, the length of the Y axis direction is Dy, and the radius of curvature of the substrate surface of the hologram element in the X axis direction is Assuming that the radii of curvature in the Rx and Y axis directions are Ry, −1.0 ≦ Dx / Rx ≦ 0 (4) −1.0 ≦ Dx / Ry ≦ 0 (5) The observation optical system according to claim 1, wherein: 14. A main unit incorporating the observation optical system according to claim 1, and observing the main unit such that an exit pupil of the observation optical system is held at an eyeball position of an observer. A head-mounted image display device, comprising: a support member that supports the head of a subject; and a speaker member that provides sound to the ears of the observer. 15. The main body part includes an observation optical system for a right eye and an observation optical system for a left eye, and the speaker member includes:
15. The head-mounted image display device according to claim 14, wherein the head-mounted image display device is configured to include a right ear speaker member and a left ear speaker member. 16. The head mounted image display device according to claim 14, wherein the speaker member is constituted by an earphone. 17. An image sensor arranged on an image plane for imaging an object image, a brightness stop arranged on a pupil plane for reducing the brightness of a light beam from an object, and the image plane and the pupil plane An imaging optical system having an imaging optical member arranged to guide the object image to the image plane, wherein the imaging optical member includes at least a second prism member and a first prism member, A second prism having at least a third entrance surface for causing a light beam from an object having passed through the aperture stop to enter the second prism with a second prism medium interposed therebetween; and a light beam outside the second prism. And a third emission surface for emitting light emitted from the second prism into the first prism with at least a first prism medium interposed therebetween. Surface and light within said first prism A reflecting surface for reflecting a line, and a fourth emitting surface for emitting a light beam outside the first prism, wherein the second prism and the first prism include the third emitting surface and the fourth incident surface. And the reflection surface of the first prism is formed as a concave curved surface that gives a positive power to a light beam when reflected, and An imaging optical system, wherein an exit surface and the fourth incident surface are formed from a flat surface or a cylindrical surface. 18. An image sensor arranged on an image plane for imaging an object image, a brightness stop arranged on a pupil plane for reducing the brightness of a light beam from an object, and the image plane and the pupil plane. An imaging optical system having an imaging optical member arranged to guide the object image to the image plane, wherein the imaging optical member includes at least a second prism member and a first prism member, A second prism having at least a third entrance surface for causing a light beam from an object having passed through the aperture stop to enter the second prism with a second prism medium interposed therebetween; and a light beam outside the second prism. And a third emission surface for emitting light emitted from the second prism into the first prism with at least a first prism medium interposed therebetween. Surface and light within said first prism A reflecting surface for reflecting a line, and a fourth emitting surface for emitting a light beam outside the first prism, wherein the second prism and the first prism include the third emitting surface and the fourth incident surface. And the reflection surface of the first prism is formed as a concave curved surface that gives a positive power to a light beam when reflected, and An imaging optical system, wherein the exit surface and the fourth incident surface are formed of a spherical surface or a toric surface satisfying the following condition. -2.0 <Da / Ra <2.0 (2) -0.05 <Db / Rb <0.05 (3) where Ra and Da are the curvatures on the axis having the larger curvature. Rb and Db are the radius of curvature and the outer diameter of the axis with the smaller curvature. 19. The fourth prism according to claim 1, wherein the fourth exit surface of the first prism is formed into a curved shape so as to give power to the light beam when transmitted, and the third incidence surface of the second prism applies power to the light beam when transmitted. 19. The image pickup optical system according to claim 17, wherein the image pickup optical system is formed in a curved shape to give the image. 20. The imaging optical system according to claim 17, wherein said first prism medium and said second prism medium are formed of the same kind of medium. 21. The surface shape of a fourth entrance surface of the first prism and the surface shape of a third exit surface of the second prism are substantially the same.
21. The imaging optical system according to any one of claims 20 to 20. 22. A ghost light removing member for preventing ghost light from entering the imaging device is provided on a non-optically active surface other than the optically active surface of the first prism and the second prism that transmits or reflects light rays. The imaging optical system according to any one of claims 17 to 21, wherein: 23. The imaging optical system according to claim 17, wherein a surface shape of a fourth exit surface of the first prism is a rotationally asymmetric curved surface shape. 24. The rotationally asymmetric curved surface shape includes a free-form surface having only one plane of symmetry, and the only plane of symmetry coincides with the folded plane of the optical axis (YZ plane). The imaging optical system according to claim 23, wherein: 25. The hologram element according to claim 17, wherein the hologram element is configured to correct the chromatic aberration of magnification of both the rotationally symmetric component and the rotationally asymmetric component by reflecting and diffracting the light beam. An imaging optical system according to any one of the preceding claims. 26. An angle between a tangent plane at a position where the axial principal ray intersects the substrate surface of the hologram element and an axial principal ray extending from the stop to a surface closest to the stop of the imaging optical system is θ. The imaging optical system according to any one of claims 17 to 25, wherein the following conditional expression (1) is satisfied: 45 ° <θ <85 ° (1) 27. The surface shape of the third entrance surface of the second prism has an action of correcting at least one of rotationally asymmetric coma and astigmatism generated by the eyepiece optical member. The imaging optical system according to any one of claims 17 to 26, wherein the imaging optical system is configured to have a rotationally asymmetric curved surface shape. 28. The rotationally asymmetric curved surface shape includes a free-form surface having only one plane of symmetry, and the only plane of symmetry coincides with a folded surface of the optical axis (YZ plane). The imaging optical system according to claim 27, wherein: 29. A folding plane of the optical axis is a YZ plane,
The direction of the axial chief ray from the stop toward the surface closest to the stop of the imaging optical system is the Z-axis direction, the eccentric direction of the optical system is orthogonal to the Z-axis, and the eccentric direction of the optical system is the Y-axis direction. The axis constituting the system is the Y axis, and the length of the image sensor in the X axis direction is D
When the length in the x- and Y-axis directions is Dy, the radius of curvature of the substrate surface of the hologram element in the X-axis direction is Rx, and the radius of curvature in the Y-axis direction is Ry, -1.0 ≦ Dx / Rx ≦ 0 (4) −1.0 ≦ Dx / Ry ≦ 0 (5) The imaging optical system according to any one of claims 17 to 28, wherein the condition is satisfied.